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Need some Relay Help

1K views 9 replies 4 participants last post by  martindt 
#1 ·
I had this grand idea on how to hook up my headlight LEDs while having my DRL lights turned off using relays, but I've fudged it up somehow. :facepalm:

Here's what I tried to do. I spliced my LEDs/Halos into the power wire for the DRL/High Beam wire so that when I turn my DRL's they would turn on, but I don't want my DRL bulb to be running. So here's where the relay enters. I cut the power wire to the DRL/HB and put a relay in between. The power source I want to use to trigger the relay would be the power source to my low beams. That way the only way my DRL/HB will work is if my low beams are on, ie I want to be able to use my HBs still.

Heres a diagram of what I did..



So what happens now. The LEDs/Halos work fine, but I can't get my Low Beam to turn on and when I try to use my HB they turn on for only about a second before it turns off... :help::headbang:

Also, I should mention that my Low Beams are HIDs. Not sure if that makes a difference or not.

And this is the relay that I used. 12VDC/40A SPST Automotive Relay Model: 275-001

Any thoughts?
 
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#2 · (Edited)
Which side of the relay did you wire power for your LED/Halo the 30 (input) or 87 (output) power.

I am going to assume you used the 30. This explains why your LEDs work fine. This part is always 12V constant.

Assuming that it sounds like you are overloading your low beam circuit. What is happening is the low beam circuit is trying to pull double duty (with HIDs it's more load) and it can't handle it.

What I think is going on is when you hit your low beams the power is split between powering the relay and powering the HIDs. The ballasts attempt to fire up but don't have enough juice. The low beam powers the relay coil for a second moving the power from the 30(input) to the 87(output) and your DRL/HB turn on. Then when the circuit gets overloaded your low beam switch power turns off or gets weak enough that the switch in the relay returns to the open position and the DRL/HB turn off.

To test this. Simply remove the low beam splice and connect that wire directly to the battery positive. If everything works after that find another switched source or simply install an auxiliary switch yourself. I think if you had normal non HID bulbs you would see that the low beams would be on but extremely dim.

Also make sure you have blown or melted your low beam fuse.

Hope this helps. I may be off but on paper it sounds right. It's also possible your ground is bad too. You can test that first by removing the splice from the 85 side and connecting it directly to battery negative or other good ground.
 
#3 ·
Well, let me explain a little further.

The LEDs are hooked up to the DRL/HD power wire before the relay, so they really shouldn't even be a part of the equation. I think you're right about me not having a good enough ground and the power wire. I'm going to try splicing into the Low Beams power line before it hits the HID ballast and see if that helps and try giving it its own ground instead of splicing into the low beams ground.

Also, I moved the ground from the DRL/HD ground to the low beam ground and the HD stayed on, but the light wasn't nearly as powerful and it was flickering, so again that supports your bad ground and power theory. Thanks for the help. Hopefully it works, if not.. Well I'll post again either way. :)
 
#6 ·
I thought we spoke in English on this forum. I wish there was an over-my-head Smiley, but I guess I'll use this one :drinky:
Haha, I learned all about this during lunch at work. Give relays a quick read, they're pretty simple, but advanced creatures or at least I thought they were. :rolleyes:

Rather than attempt another splice before the low beam test the easy and simple options directly to the battery.

Unsplice the ground and put it directly to battery negative. If the problem is fixed your ground splice is the issue.

If that doesnt fix it unsplice the low beam power splice and connect it directly to the battery positive. If the HID's and everything else works then you know you have an issue with power.

If none of those fix the problem either your fuse for your low beams is now blown (from an overload), your relay is defective, your wiring is melted internally, the ballasts are bad, the HID bulbs are bad, or the headlight switch is bad.
Good call so far. Just checked the ballast, bulb, fuses. All good still.

I moved the splice into the power wire to before the ballast and now the high beams work! But the HIDs still don't, but I haven't moved my ground off of it yet, so I'll try hooking up my ground to the battery like you suggested. I'm still worried that your theory that the low beams can't pull enough power, but I can't imagine that to be the issue if the low beams are only using 35W, but then again thats once they are stabilized... Uhg *fingers crossed for bad ground*
 
#5 ·
Rather than attempt another splice before the low beam test the easy and simple options directly to the battery.

Unsplice the ground and put it directly to battery negative. If the problem is fixed your ground splice is the issue.

If that doesnt fix it unsplice the low beam power splice and connect it directly to the battery positive. If the HID's and everything else works then you know you have an issue with power.

If none of those fix the problem either your fuse for your low beams is now blown (from an overload), your relay is defective, your wiring is melted internally, the ballasts are bad, the HID bulbs are bad, or the headlight switch is bad.
 
#7 ·
I am going to assume this is related to your low beam power more than ground based on what just happened.

So if you remove the splice thats before the ballast and move it directly to the battery and everything works, then you may just need to rethink your power source. If you do and the low beams still dont work recheck your fuse.

For splicing into the low beam circuit you should really be using an add-a-fuse. They can be had at autozone for like 5-10 bucks plus the cost of a 15? amp fuse. You simply remove your fuse from the low beam circuit. Install the add a fuse. And install 2 fuses into the slots for the add a fuse. One fused section goes directly to your low beam circuit (through the add a fuse itself) and one portion goes to the addition (splice wire) through the fuse you added. I have this same setup powering the fogs in my Camry. The only difference is that I am using a Toyota Relay, and my 12V constant comes from the fog switch power (Which comes from the battery). So when the low beams are on the powers the coil which moves the switch over but the fogs dont have power unless the switch is supplying power to be redirected by the relay.
 
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#8 ·
Yea I bought some inline 15amp fuses/holders. Its been in there through this whole time. :thumbsup:

I pulled the ground splice off the HIDs after the ballast and moved it to the battery ground. Works like a champ now. :clap:

I don't even want to remember how many solder, cuts, heat shrinks, twists, and strips I did to get this to finally work, but it was worth it. Sad part is that it'll take me probably 15 minutes to wire up the other one compared to the 5-6 hours it took me for this one lol. Thanks for all your help. I'll post up the result when I'm finished.
 
#9 ·
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