Lights dim at idle, voltage regulator?

[mk2-1jz]

I've noticed my lights dim down when the car is at idle, they brighten up as more power from the alternator turning is delivered. Is this supposed to happen, or is there a problem with the voltage regulator? If there is, where is it located on the car, and are there ways of testing it with a multimeter to dertimine if it needs to be changed?

thanks a lot, Jamie

[dhamaka127]

I would think its your Alternator going....

you can get that tested at any auto zone....

[Mike Gerber]

What you are describing seems like normal behavior. Try it with any other car Camry, Chevy, Ford or even a Mercedes and they will do the same thing. The faster the alternator spins, the more voltage is produced.

As far as the regulator, they are internal to the alternator and are not usually replaced without replacing the whole alternator. However, as I stated above, your's sounds normal. If you are not comfortable with it, get the alternator tested, if just for piece of mind.

Mike

[mk2-1jz]

I would also suspect the alternator but I changed it about 8 months ago, its a refurb and seems to be in decent shape. I dont understand something though, if the regulator is intergrated inside the alternator what is this piece? I found this on rock auto, its listed under electrical --> voltage regulator, is this the internal piece?



Autozone is a good idea, its free right? I'll get them to check the battery too, I have a feeling it might be on its way out, what are the most common tell tale signs other than it losing charge compleatley?

thanks, Jamie

[dhamaka127]

Yes Autozone will do it for free, also the battery check for free!

it looks like it dissipates heat. I am not from what? I can be wrong...someone here is bound to know.

Good luck.

[white90dx]

Originally Posted by 88camrycrazy

I would also suspect the alternator but I changed it about 8 months ago, its a refurb and seems to be in decent shape. I dont understand something though, if the regulator is intergrated inside the alternator what is this piece? I found this on rock auto, its listed under electrical --> voltage regulator, is this the internal piece?

The regulator is internal, but not impossible to get to. You can remove the alternator, disassemble it and you can find the regulator, brushes and other things that can be replaced if you can find parts.

If the dimming is severe, check the alternator (it's probably not the regulator though). If the dimming is slight, it is probably normal...

-Charlie

[mk2-1jz]

The dimming is not severe but its very noticable, its winter here now so it shows more on the snow. At idle the lights seem very dim but when you build up the rpms the lights get bright bright, I thought it was the headlights i put in, 4000K halogens, i figured maybe they took more juice than the others, but my dash lights brigheten up and the fan blower speeds up with the extra spin of the alternator. Is there maybe too much load on the circuit for it to remain a constant brightness at idle?

[90camdx4]

i dont think its a problem...my 90 does the same thing also, remember the car is an 88 almost 20 yrs old so wear and tear etc.

[monito]

you mentioned that you have a refurbed alt. chances are the alternator is on it's way out.

you can test the alt by connecting a DMM to the + of the battery, and the surface of the alternator. I posted some specs on voltage drops a few months ago. as soon as i find it, i'll post it.
otherwise, the voltage drop specs are available on the camry manuals stickied on TN

[TBayToyotaBoy]

Unless you buy a dealer alternator, you'll probably keep getting this problem. I've had it on and off with all of my Yotas over the years. Only when I manage to find a genuine Denso alternator at work (the wreckers') can I get the problem to go away. Bosch rebuilt alternators (which I have bought new before) work fine for about six months before the dimming problem returns.

It's annoying, but unless you want to buy an 80-amp alternator (the V6 Camrys mostly ran 80amp, but the pulley is wider so be ready to swap it out) or a crazy-expensive Denso unit, you can learn to live with it.

Hope this helps a bit more...

[mk2-1jz]

Are the mounting brackets of the V6 alternator the same as the 3sfe or easily modified via grinder and welder and do the pullys switch over? If that idea would work thats probably what I'll do, I'm also running a demanding sound system that would benefit from the extra power. But thats unrelated to the problem because I shut if off to make sure it wasnt that causing the dimming problem, besides I also have a ginormous cap and the bass hits dont make the lights dim, its really related to the alternator at low idle speed.

[TBayToyotaBoy]

I'll try to get you some pics tonight of the two alternators, but YES--the mounting brackets for the I4 and V6 alternators are the same. Only difference is the pulley (I4 has five ribs, V6 has six), which can easily be swapped with an impact gun and a vice.

As an afterthought: I've pirated parts out of an I4 alternator to keep my V6 running before. The brush holder and the voltage regulator are (more-or-less) direct-fits between the two. I HAVE found, however, that the aftermarket designs are slightly different than Denso (OE) alternators. This makes the internals incompatible.

[TBayToyotaBoy]

Here is what the alternators look like. The I4 alternator is on the left, and the V6 on the right. Note the extra v-groove on the V6 rig.




And here is what the voltage regulators and brush holders look like. Again, I4 unit on the left, V6 on the left. They're identical:

[mk2-1jz]

hey thanks a lot for the pictures, that definetely gives me another option if I cant figure out things with the one i have. What causes the rebuilt alternators to start dimming after a while? Is there anything that I can replace inside the alternator that might fix the problem? At this point I'm almost certain the problem is inside the alternator.

You also mentioned that the genuine denso alternators were not interchangeable with the aftermarket ones, how can I tell that the one I have now is a genuine denso that has just been refurbished or just an aftermarket one. I'm kinda pissed now becasue I gave up my genuine denso (which was the origianl one and screwed up) to trade for some money off of the refurb. If i would have known I could fix it myself that probably would have been the best.

thanks a lot, Jamie

[monito]

FYI, according to the Toyota Dealer Parts guy @ the EG Toyota, the alternators from Toyota for the Gen2 are also refurbed Denso's. The Duralast alts from AutoZone are also refurbed Denso's but come with a lifetime warranty.