Pricey? No way! Shipping might be pricey though.

It looks super simple to wire and use. Anything else you find will me much more complicated!

-SP

 

Good to know I found something nice!

A relay module will be on or off so it will work but you won't have a dimming function.

There are probably a bunch of timer modules based on the 555 chip on feebay. You could use one of those to to make a delay function. And if you wire it up to LEDs, you could probably add a large capacitor which will give you a dimming effect when the power cuts off.

I'll try to take a look at home tonight, feebay is not a website I like to go to at work!


With regards to your control box, have you looked at the PCB to see if a fuse is blown? It will be marked F1 or Fx (x = some number). It will look like a resister. Put a multimeter to it on resistance or continuity setting. Should be short or 0ohms if good and infinity/open if bad.

The fuse isn't on the PCB, it's on the wiring itself. Inline fuse holder, which is fine. I can take some photos of the PCB a little later.

EDIT: I understand better what you mean. I'll open it up and take a look after work.

 

Halo! Try it out! That way I know it works before I attempt it. And I'm sure you will leave us with some great tips.

 

A relay module will be on or off so it will work but you won't have a dimming function.

There are probably a bunch of timer modules based on the 555 chip on feebay. You could use one of those to to make a delay function. And if you wire it up to LEDs, you could probably add a large capacitor which will give you a dimming effect when the power cuts off.

I'll try to take a look at home tonight, feebay is not a website I like to go to at work!


With regards to your control box, have you looked at the PCB to see if a fuse is blown? It will be marked F1 or Fx (x = some number). It will look like a resister. Put a multimeter to it on resistance or continuity setting. Should be short or 0ohms if good and infinity/open if bad.

 

Here is the control box. No fuse, from the looks of it. It does have an inline fuse in the power wire on the plug side.

On the right is the plug side, the two red wires coming from the dome light plug and the black being e dedicated ground with a ring terminal. Left are the wires for the two light bulbs. Can someone figure out what could break causing the entire thing not to work at all?

 

Take a picture of the bottom (trace side).

The board uses mostly low power stuff and rarely go bad, maybe the diodes or capacitor.

D1 and D1 are diodes. Put your multimeter on resistance, try 2M ohm and move down to K ohm if it doesn't work. Put the leads on each end of a diode, check resistance (high or low) and then reverse the leads. The resistance should be opposite.

For capacitor C, put the meter on highest resistance. Put the leads on it for a couple of seconds, then reverse the leads, you should see resistance go up or down slowly and then infinite. If it doesn't work, reverse leads again. If nothing, capacitor could be bad... but this is not guaranteed... unless you have an expensive meter that can test capacitance.

Here is the control box. No fuse, from the looks of it. It does have an inline fuse in the power wire on the plug side.


On the right is the plug side, the two red wires coming from the dome light plug and the black being e dedicated ground with a ring terminal. Left are the wires for the two light bulbs. Can someone figure out what could break causing the entire thing not to work at all?

 

Here is a timer module on feebay for $2.19, but it will take 2-3 weeks from China. I can't tell exactly from the picture, but I'm guessing to use:

Gold metal screw on top of small blue module controls delay time.

Green 2 pin header on end for 12v power... check for ground, do not reverse, connect the power intended for the light bulb to this.

Green 3 pin header for relay function... COM is common for power to light, you will use either CK or CB which shorts to COM. One of them is connected to COM when there is no power, when 12v power is connected to the board, it will disconnect after delay and then reset when 12v is removed. The other is opposite (it will connect after delay).

You will connect the light bulb ground (either pin for incandescent bulb to ground or metal part of car / LED negative to negative of power source). Then the other pin of incandescent bulb (LED positive) is connected to COM. Power to the bulb (12v source or same 12v going to module) for incandescent bulb or whatever supply positive you use for LED lights to CK or CB.

*** LED may not use 12V, check voltage of LEDs you get.

I would test the module with a meter before connecting a lamp. Put power to the module and test which pin (CK or CB) is connected to COM and then disconnects after delay.

http://www.ebay.com/itm/12V-Delay-T...ith-NE555-Oscillator-HM-/400662832934?pt=LH_DefaultDomain_0&hash=item5d495da726

 

You will connect the light bulb ground (either pin for incandescent bulb to ground or metal part of car / LED negative to negative of power source).

Let me quickly ask you about this statement. You differentiate between incandescent bulbs and LEDs. So the LED can't be directly grounded to the metal, it needs to go to a negative? Because the original setup of the floor lights is that they only take power from the dome light, and have their own ground ring terminal coming out. So the bulbs are grounded to the metal and provided power from the plug. Is that why the LEDs didn't work, because they were grounded and had no negative? Could this have damaged the control box? I'm struggling to understand this.

 

If you use low power LEDs, you may try to connect a large capacitor across the LED power pins (check polarity + to +). That MAY give a short dimming effect when the capacitor discharges and the voltage drops. NO guarantees... many factors will come into play here.

But only try this after you get the timer working.

 

There's not much there to go wrong, you can test the resistors with a DMM and you can test the diodes with a DMM and the Q1 and Q2 are what I fear is what died. Have to google the part number on q1 and 2 to know what they do and how to test them

 

There's not much there to go wrong, you can test the resistors with a DMM and you can test the diodes with a DMM and the Q1 and Q2 are what I fear is what died. Have to google the part number on q1 and 2 to know what they do and how to test them

I believe Q1 and 2 are transistors? Q1 is A1015 GR11 and Q2 is C982 1L. I'll google that.

I'll add plug it back in and just see if the board is getting any power. Sometimes corroded or loose terminals in a fuse holder are the problem and not the unit itself.

-SP

You mean just test power at the end of the wire where it attaches to the control panel?

 

I'll add plug it back in and just see if the board is getting any power. Sometimes corroded or loose terminals in a fuse holder are the problem and not the unit itself.

-SP

 

those are all cheap readily available components, just replace them one at a time till it works. Grab a bag of each part from eBay, replace all your bad parts, then you can build a couple duplicates (grab bare PCB, cut to same size, drill holes to match, and use wires to connect across instead of traces or learn how to etch) and sell them to offset the costs of materials.

 

The problem here is many of the discrete components on sale on ebay are cheap imitations or 2nd grade. They may work or may not... unless you test them before soldering them in, you may be adding more bad parts.

Its a lot of work versus just getting a new delay board I showed.

 

Oh, one more question for you guys. Do you know why the key ring light and floor lights both draw from TWO red wires in the dome light plug? What's the difference between those two? The four wire plug has two red and two green, and I don't know which to use for power when wiring in the 12V delay timer.

 

Jesus this is weird. I just tested the power at the floor lights, since I was taking out the key ring light. So the end of one wire from the plug that goes TO the PCB gets 12V power, the other gets 0.8V power. So I decided to test whether it went to the other side.

So the leads coming out to the bulbs get full 12V power when I touch the positive end of the multimeter to the positive lead of the bulb on the PCB and the negative end of the multimeter to a ground (a bolt), but if I touch the negative end of the multimeter to the negative lead of the wire from the bulb on the PCB, it shows 0.015V. Basically, the power is there, but it seems like the negative leads of both bulbs don't ground properly? Is that right to assume from this data?

So could I just cut off the negative leads of the bulbs and ground them using the ring terminal coming out of the other end of the PCB?

 

From what I know of some older cars, the 12V was constant (always attached) and they switch the power on and off by the ground wire. I think this is what you are seeing. Since you touch the constant ground (bolt), you get 12v, but if you touch the negative wire (switched), you get 0v when it is off. The 0.015v is either leakage or meter error.

Fair warning: I really haven't played with car electronics (or any consumer electronics) in a long long time...

 

Good. I'm the same why. I want to know what when wrong and learn something in the process.

I don't think it's obvious that Q2 is bad. The center lead of Q1 goes to R4, then onto one of the leads of Q2. It could be necessary for voltage to go through R4 to that lead of Q2 to allow current to pass from the negative bulb through the other leads of Q2 to ground. In other words, the transistor is normally "off", and providing a voltage to the "base" lead turns it "on". I think this would be the NPN type of transistor (as opposed to PNP). Having two transistors on the board makes it a little harder to figure out how it works.

I know that are ways to test transistors, at least for complete failure. For example, there shouldn't be continuity between all three terminals. I think they can be tested with the diode setting on your multimeter. Look it up. Not sure if they can be tested reliably in circuit.

 

I guess I'll be Googling how to test transistors! Yeah I have already learned a lot from this thread. I'd like to get to the bottom of this, even if I don't end up fixing this control box.

 

Had to get out of bed to ask this, otherwise I won't be able to sleep.

You mentioned the dome light connector only had the 2 red wires.... no ground? If so, are you connecting the black ground wire on the right to the car ground? The circuit won't work without it, the second stage of the two stage transistor circuit uses the car ground.

 

Yep, the connector itself has no ground. The ground on the board goes to a ring terminal that I hook up to a bolt on the body. I know this is a good ground because my key ring light works perfectly grounded there (same deal, delay then fade).

 

The factory dome light plug is 4 wires, but the dome light only uses two. This plugs into where the dome light goes, and allows the dome light to be plugged into it. Just a passthrough. It doesn't affect the dome light, no dimming on that. Just skims power from it. Fuse is inline with one of the power wires.

Q2 shows no continuity on three combinations, one shows 1.6V, one shows 1.7V, and one shows 0.7V.

Q1 shows no continuity on three combinations, two at 0.7V, one at 1.7V.

That is, if I understood your testing method correctly. I tested between two of the three pins on one transistor at a time, then swapped positive and negative and did the same. Nothing between the two transistors, just on one at a time.

Does that say anything?

 

That Q2 is suspect. Even in circuit at least 2 of those tests should be 0.7V or lower. Because R3 and R4 also connect two of those terminals in parallel, those readings should be even lower.

Looking at the bottom of the board (like in the 2nd picture), with Q2's leads numbered 3-2-1 from left to right...Let me guess, 3(+) to 2(-) was 0.7V, and 1-to-3 and 3-to-1 were the 1.6V and 1.7V?

You may need to unsolder that Q2 transistor from the board to be certain of the test. Or you could unsolder one of the leads from R3 or R4 to completely isolate all the Q2 leads from each other, then test again.

It should be 3(+) to 2(-) 0.7V and 3(+) to 1(-) 0.7V, all others no continuity.

See this page (among others on the Internet) for testing transistors:
http://www.vetco.net/blog/?p=184

The Q2 leads left-to-right (in your picture) 3-2-1 are base-collector-emitter.


And as far as the connector...that means that the voltage coming in must go back out unimpeded to power the dome light. I'm not sure how that happens because it looks like the circuit goes through Q1, then through 2 resistors before going back out of the other red wire. :dunno:

 

3-2 was 0.7V indeed, 1-3 was 1.7V, but 1.6V was 1-2.

I can unsolder it and test it soon, just to be sure.

No, no. Voltage doesn't have to come back out. The male and female plugs are connected directly, so it's just an extender with two wires spliced in to power the floor lights. Voltage goes straight through to the dome lights.

 

OK, yeah, it looks like 1-2 is also measuring the circuit R3 to R4 to 3 to 2. But 3(+) to 1(-) should not be no continuity, even in circuit.

I'd pull it out and test out of circuit. It can be a little tricky unsoldering something with 3 leads, that's why I suggested just removing one of the R3 or R4 leads. But if you remove Q2 and it's bad then you had to remove it anyway.


Thanks for explaining the connector. I'm still unclear on one thing. What changes to turn the floor lights on? One red wire is always 12V, the other you measured at 0.8V (both to body ground). Does this change depending on if the door is open/closed? Or if the dome light is turned on?

 

I guess the second wire changes somehow depending on whether the door is open? The door opening grounds the switch. When it's grounded, the second wire shows 0.8V and the first shows 12V. I didn't test it with the door closed and the door switch ungrounded.

So I took it out and tested it. 3-2 is 0.7V like it should be, 3-1 is 1.9V, and 1-2 is 1.6V. Safe to say it's a broken transistor?

And can you help me pick out a replacement to solder in?

 

Here it is, in a clamp for proper testing.

Also checked out that testing transistor site, so this is an NPN transistor? Interesting, a data sheet said it was a PNP. But that makes sense because the outer pins go to grounds :/

 

Well this site says PNP, but the datasheet there says NPN.

http://alltransistors.com/transistor.php?transistor=30871

Also, I just noticed it says darlington transistor which is like 2 transistors paired together as one. I'm no expert on transistors, so I'm not sure if your readings show that it's bad.

 

Well this site says PNP, but the datasheet there says NPN.

http://alltransistors.com/transistor.php?transistor=30871

Also, I just noticed it says darlington transistor which is like 2 transistors paired together as one. I'm no expert on transistors, so I'm not sure if your readings show that it's bad.

It should be NPN really, but who knows...

I'll wait for Woz to chime in to see if he knows what's up. Hopefully this is the broken part!

Dudes you rock. :thumbsup: TN amazes me all the time with it's knowledge base & willingness to share. Apperciate it gentlemen

Right? This community is simply amazing. Always thankful.

 

Dudes you rock. :thumbsup: TN amazes me all the time with it's knowledge base & willingness to share. Apperciate it gentlemen

 

To complicate things, that link I posted with the datasheet may not be the exact equivalent transistor in that these darlington transistors can vary with having internal resistors and diodes built in.

I'm leaning toward saying that transistor is not the problem, if it is in fact a darlington.

I came across this interesting 8 minute video talking about darlington transistors. The second half of the video is particularly interesting because he discusses how these transistors test differently than ordinary transistors -- you will get similar readings to what you got.

 

I think your transistors are fine. The darlington has two base-emitter junctions in series, so you wouldn't see 0.7v for that particular measurement.


If anything is likely to be damaged, I'd suspect it to be d1. It's a small signal diode and can't handle too much current(maybe 200mA) but has to supply the lamps you try to light with it. The inline fuse is supposed to protect it, but can easily be replaced with something too strong for the diode. If the diode still reads 0.7v forwards, then it's fine though. If its shot, I'd replace it with a 1n4001 which would be good for 1A.

 

When I test D1 by setting my multimeter to continuity and touching each side of it, it shows no voltage but beeps that it has continuity. Does that mean it's broken?

 

They look like the same kind of diode, so yeah, they should both test the same. The one end of D1 is not attached to anything else in circuit, so nothing to throw the reading off.

Like luns said, you can replace it with 1N4001 (50V, 1A rating) or a higher rated diode (1n4002, etc.) These should be cheap and easy to find at any local electronics store.

http://en.wikipedia.org/wiki/1N4001

I'm still a little curious how the input voltages on those two red wires change when the door is opened/closed. I'd like to understand how this dimmer works, and how a bad D1 stops it from working. :headbang:

 

I'll get you the change in input voltages soon, I'm very curious as well. If you guys are anything like me, you'll be obsessing until it's all solved as well

I'm heading to a Radioshack to pick up a 1N4001 and solder it on instead of D1, and solder on the Q2 transistor (oh boy, that won't be fun). Then I'll test it all and report back!

 

Okay I bought a new diode and wired it in. Also soldered back the transistor

Plug it in, nothing. Still doesn't work. It's definitely not the diode. Tested the new diode, it works just fine.. 0.7V drop one way, no continuity the other. It's something else....

Also tested the wires. With the door open, center wire is 12.6V and side wire is 0.8V. When door is closed (and door switch ungrounds), both are at 12.6V.

 

I was afraid that the diode wouldn't fix it because if that red wire is at 12.6V all the time, then current would not flow backward even without the diode there (with just a wire there).

This is my take on how this circuit should work...

It looks like the center red wire provides 12.6V, goes through D1, then this path splits at R5 (which is just a wire). The R5 path leads directly to the bulbs. The other path goes to the emitter on Q1.

When the door is open the other red wire is at 0.8V. This allows the base of Q1 to remain at low voltage because current passes through R1, R2 and D2 out of the 0.8V red wire. The capacitor also charges up since the voltage difference is 11.8V.

As long as the base of Q1 is low compared to the emitter, current passes through the collector (center lead) of Q1. From there is drains to ground through R3, and it leads to the base of Q2 through R4. When the base of Q2 is high, Q2 becomes active and allows the current from the bulbs to flow to the ground (bulbs light).

Now when the door is closed, the side red wire goes to 12.6V, but this voltage doesn't propagate because D2 prevents current flow in that direction. Transistor Q1 is held in the active state by the charge in the capacitor. The current that used to be flowing out of the side red wire (when at 0.8V) now is absorbed into the negative side of the capacitor. It takes a few seconds for the capacitor to absorb the charge, so Q1 remains active, or slowly becomes inactive. As Q1 becomes inactive, it causes Q2 to become inactive, and the bulbs goes out.

What does this all mean? Well, (hopefully) if you test the voltages at different points (negative lead on ground(black), positive lead at the various components), and do this with everything hooked up and the door open and closed. You should be able to figure out what is changing and not changing between the open/closed.

It wouldn't hurt to measure the resistance of all the resistors. Maybe you already did this...I can't remember at this point. :facepalm: If any are bad it will prevent the transistors from working properly. For example, if R3 is 3.22 kOhms, but should be 10.2 kOhms, then maybe you're leaking too much current to ground, and the base of Q2 may not be getting enough voltage through R4, so Q2 is not becoming active.

 

I was afraid that the diode wouldn't fix it because if that red wire is at 12.6V all the time, then current would not flow backward even without the diode there (with just a wire there).

This is my take on how this circuit should work...

It looks like the center red wire provides 12.6V, goes through D1, then this path splits at R5 (which is just a wire). The R5 path leads directly to the bulbs. The other path goes to the emitter on Q1.

When the door is open the other red wire is at 0.8V. This allows the base of Q1 to remain at low voltage because current passes through R1, R2 and D2 out of the 0.8V red wire. The capacitor also charges up since the voltage difference is 11.8V.

As long as the base of Q1 is low compared to the emitter, current passes through the collector (center lead) of Q1. From there is drains to ground through R3, and it leads to the base of Q2 through R4. When the base of Q2 is high, Q2 becomes active and allows the current from the bulbs to flow to the ground (bulbs light).

Now when the door is closed, the side red wire goes to 12.6V, but this voltage doesn't propagate because D2 prevents current flow in that direction. Transistor Q1 is held in the active state by the charge in the capacitor. The current that used to be flowing out of the side red wire (when at 0.8V) now is absorbed into the negative side of the capacitor. It takes a few seconds for the capacitor to absorb the charge, so Q1 remains active, or slowly becomes inactive. As Q1 becomes inactive, it causes Q2 to become inactive, and the bulbs goes out.

What does this all mean? Well, (hopefully) if you test the voltages at different points (negative lead on ground(black), positive lead at the various components), and do this with everything hooked up and the door open and closed. You should be able to figure out what is changing and not changing between the open/closed.

It wouldn't hurt to measure the resistance of all the resistors. Maybe you already did this...I can't remember at this point. :facepalm: If any are bad it will prevent the transistors from working properly. For example, if R3 is 3.22 kOhms, but should be 10.2 kOhms, then maybe you're leaking too much current to ground, and the base of Q2 may not be getting enough voltage through R4, so Q2 is not becoming active.

Quick question. How do I find out what resistance a resistor should have by its stripes? I'll test all the resistors but I want to compare them to known proper values.

I can also test the voltage in certain areas. When I have less of a headache, I'll reread your comment and test every step. I had to read your comment three times as it is, not feeling my best.

make sure you're getting a solid ground from the door switch, you can get enough ground to light a bulb or LED but not enough ground to run something more sensitive and complicated. If you supply a solid ground from the battery to the board will it work?

I'm absolutely getting a good ground. My key ring light works perfectly, and it's the same system. Passthrough connector, inline fuse, and control box for fading.

Are you using bare LEDs that you bought at Radio Shack? Bare LEDs have 0ohm resistance (appear as a short) to the circuit and will blow the circuit. They need a series resistor to limit the current. LEDs sold as a bulb replacement have resistors built in, but bare LEDs will not. The bare LEDs will also not be bright enough for you as they are for indicators not illumination. This may be why the control box is dead if you tried it out with the LEDs before anything else.



You are correct, it does not in any way prove Q2 is bad. But the other measurements appear to show that the rest of the circuit is good, so if we 'simulate' Q2 on by shorting and the bulb lights, then it is a safe assumption that Q2 is bad. This of course also assumes I am correct is reading the other components and how the circuit works.



The culprit is unlikely to be D1. Current to be bulbs must pass through D1 before getting to the bulbs and we know the output to the bulbs is good. That is not to say D1 is not bad. It could well be permanently shorted, but I don't think that would affect the function since it appears the purpose for D1 is to block reverse current going back to the 12v source. At this point, we don't care if there is reverse current.



This measurement shows power going to Q2 and Q2 should turn on connecting the car ground to the negative output for the bulbs. 12v output to be bulb is constant after D1 and we know the power is there by you shorting Q2, so why no output power unless Q2 is not turning on. These discrete transistors require very little current to turn on, so if we can measure 11.7v there, it should turn on.

You can still do many more measurements, tests, and analysis, but my guess (and this is based on me interpreting and seeing the other measurements you made were good) is still Q2 being bad.

I'm out of town all week and don't have a lot of free time or internet access, but I will try to trace out the circuit and take a second look.

D1 was definitely bad, it was showing continuity both ways. But it was good at some point when it was still not working I think... definitely not the issue.

I was using 74 LEDs, not Radioshack ones. They are made for automotive use and work in stock applications, so I can assume they have built in resistors. I also used these LEDs instead of the stock 74 bulbs in the HVAC lighting system. They look like this:

If you think Q2 is bad, do you have any idea what I can replace it with?

Only have a few minutes here and there these days to post, so no time to be as thorough as I'd like.

DrZ's description of the circuit function is correct and complete.

My concern for D1 was that it may have blown open (eg took the hit of a fuse). Failing as short wouldn't hurt it functioning, and the new diode is for sure good, though it makes q2 the weak link in the chain now.

R1 should be 1k instead of 3ish: the gold stripe indicates its a 5% tolerance, in which case there should only be four stripes total. I don't know whats up with the dot but i don't think they're supposed to be a fourth stripe. Brown black red is 102, which means 10*10^2 = 1000. R1 may be screwy, but 2k more shouldn't matter given r2 180k. Unless r2 isn't what it should be either.

Try shorting the middle pin of q1 to r5. If the lights light, then q2 is good and either q1, r1, r2, d2 or c1 are bad. If they don't light, then q2 or (less likely) r3 or r4 is bad. You can also try grounding the negative terminal of c1: if the lights light, then d2 or r1 are open.


Also, with door open and door closed, measure voltages (relative to ground) at both terminals of r2 and r4 (4 places in total). We can read from that what's happening. Give each measurement some time for c1 to charge/discharge and note the final value and whether it moved slowly getting there or got there instantly.

Oh, thanks for explaining the resistors. I'll test them very soon. I'll also try shorting the middle pin of Q1 to R5. I doubt D2 is bad, it tests fine.

I missed these earlier..


Sounds normal




Is this 1.7 (normal) or 11.7 (bad)?

That's for sure 11.7V, not 1.7V.