Battery Light on.......then off.

Hello
First post, so any help would be appreciate. I will return the favor whenever I can.

First, just bought my first Tacoma a few weeks ago after wanting one for many years. Figured I'd start with the 2 wheel drive then after some years, more into the 4x4 version. It's a 2005 Tacoma Access Cab 2 wheel drive, 2.7L. It only has 70,000 kilometers (or 43,500 miles) on it. Test drive went great, no problems at all, so I bought it. Last week the battery light came on. First thoughts were Alternator or Battery. Both have been taken out/off the truck and taken to a shop that specializes in alternator repairs. Both are as good as new. Truck works perfect, starts great, only thing is that annoying battery light. (I know..put a piece of tape over it, but that is not me)

This week my wife was driving in our car in front of me as I was driving the truck, and she noticed that there were no lights on the front of the truck (daytime running lights) but as we pulled down our road, the truck turn signals on the front were light up (DRL's on).

Now with me in the truck, the battery light was on, until I hit a pothole at the front of our road, then the battery light went out. (This is around the time she noticed the DRL's on)
Next day started the truck, battery light on. Drove about 5 miles , light went out for the rest of the day. Next day, same thing. Start the truck, battery light on drive 5-6 miles, battery light goes off (and so you know, many potholes/rough sections I have to go over this first 5-6 miles)
Right now, truck is sitting in the yard with the battery light on.

Now the questions.
The only fuse I can find that seems to go with the DRL's are the 15 amp blue fuse in the fuse box under the hood. Fuse is good. Is this the correct fuse? (Book does not say where t is)

It now sounds to me like a bad connection some where's, but I would like to know if anyone else has had this problem and if so what did they do to fix it. Or anyone have any idea's how to fix this or what it might be before I spend hours looking for the cause.

I see lots of post on how to disable the DRL's, but not only do I need to have them in Canada as part as the inspection process, I like them on and not to mention...the battery light annoys the crap out of me! lol

Long post for being my first, but the more info I provide, the better chance of finding the problem I hope.

Again, thanks in advance for any help you can provided.

Edeh

 

Start looking for a loose connection somewhere. At the lights? Light switch? Also, check the parking brake switch. On my 2012, the DRL's don't come on until l release the parking brake. Maybe there is a problem with your parking brake? Sometimes the parking brake mechanism in the rear drums gets rusted and won't allow the parking brake to fully disengage. There could also be excessive play in the parking brake cable? Hope you find the problem!...

 

Check with a multi-meter when the truck is running vs not running. it should be at 14.xx volts while running. if not your alternator might be possibly have a bad diode cause the battery light to come off and on.

 

The battery light is turned on by a miss match of voltage between the alternator output and the battery. I agree with welterbf123 and first look for a loose connector or dirty connection. The most probably will be the one that plugs into to the alternator. A high resistance ground connecting can cause some strange problems.

 

Electrical gremlins are some of the hardest things to diagnose. I deal with this sort of thing on a regular basis on boats. Its best to stand back and simplify the issue. You already went through the first couple steps. Checking the alt and battery. Next is to check your fuse block. Their should be a main fuse for the truck. (Never popped mine open so don't know what to look for). Check all your fuses. If you don't find any loose or corroded or otherwise faulty fuses. Then comes the long process of tracing wiring and checking connections. Start with the battery and work your way in. Good luck.

 

It's been a year but I FINALLY got the problem solved...it was the alternator. Diode in the alternator was malfunctioning causing the battery light to come on and the DRL to go off. Put a new alternator on the truck and haven't seen the problem in over a month now.

 

How did you find the bad diode? I would fully charge my battery with a battery charger and test it for latent undercharging damage from the alternator problem.

The battery and charging system are codependent on each other.

 

Did the Bat light always stay the same brightness during your problem (even with the engine off but the ignition on???

 

Glad the problem is resolved. Intermittent issues like this are tough to find.

And thanks for reporting back, even after such a long time.

Way too many threads of folks seeking help are never concluded, the posters just wander off. Getting the solution helps the rest of us who may be searching for similar solutions!

 

Shadetree.... It was actually the local Toyota dealer that found the problem. I had a few other garages try to find it with no luck. I had the Tacoma in for a few recalls to be done and figured while it was there I'd take the kick to the....you know, and get them to look at it. It took 1.5 days to find the problem and fix it. (I have to say though the dealer treated good labor wise)
Canufixit.... I honestly do not remember if the light was the same brightness when the truck was on & off. If I had to guess, I would say "yes" because when I first tried to figure this out on my own, I tried it both ways and I did not notice a difference in the brightness of the battery light.
Clearwater Bill.... I totally agree with you. Though I only have a few posts in this forum, if this post helps some else with a similar problem then it's worth the update right.
Thanks to all who did reply to my original post as well.

 

Thanks!