Battery/ABS/airbag light. Theories/help!

[Myrunr2010]

So for quite a while now (year +) my battery light has intermittently been coming on. Usually at the same time my ABS light will come on. It hasn't been giving me any issues (that I knew of), still drives fine, starts fine etc. It was doing it when I bought the truck, and then didn't do it at all over the winter, them started again recently.

I don't drive where it's real dark out too often, usually I'm in the city and can't tell, but last night I was driving home and noticed that when the battery light would come on, the headlights/Interrior lights would be brighter. The airbag light was also coming on. I had an old f150 that a similar thing happened to and it ended up being the voltage regulator. Given that, I have a high suspicion that it's the voltage regulator this time, but, I don't want to go fork over cash without getting some other opinions/suggestions. I would assume that the ABS and airbag sensor come on because they aren't getting the right number of volts and are therefore throwing a code.

So, any suggestions/ideas?

 

[BrianSD_42]

I suggest you buy a scangauge or an OBD2 BlueTooth reader ($29) with Torque App (or similar) off Amazon right away.

I would want to know what is the voltage at the moment the light is coming on. The best way is to use one of the above while the vehicle is operating under normal conditions.

So problem: battery warning light (plus a bit more)

Partial solution: Use a tool so you can see the battery/alternator voltage.

 

[Myrunr2010]

Any other ideas/solutions/input that don't require the purchase of tools?

Is there any other reason that the headlights and dash lights would get brighter when the battery light comes on?

 

[BrianSD_42]

Any other ideas/solutions/input that don't require the purchase of tools?

Is there any other reason that the headlights and dash lights would get brighter when the battery light comes on?

Do you have a multimeter? You can use that manually but it wouldn't be as good in my opinion since you cannot be sitting in the front seat and using the multimeter at the same time.

Frankly a bit of investment here is needed. Perhaps your neighbor has a multimeter you can borrow. Also NAPA or Autozone may have an even more cheapo option but what is great about the BlueTooth OBD2 is that it does more than just codes, when paired with a smartphone app (free or $5) you can see a bunch of information including the voltage.

* If you can't afford $29 for an Amazon OBD2 reader or simply need another option you can go to Pep Boys and ask them to read the voltage. They read codes for free as well.
* If you are at the VMI I would assume there is someone in your class who knows about cars and perhaps even has a multi-meter you can borrow.
* If you serve (currently) then you can go to the base autoshop and they would definitely have one.
* Another option is to go to Autozone and pay the cheap rental fee for a multi-meter.

I have a high suspicion that it's the voltage regulator this time, but, I don't want to go fork over cash without getting some other opinions/suggestions. I would assume that the ABS and airbag sensor come on because they aren't getting the right number of volts and are therefore throwing a code

Your suspicions are sound but you will really want to test the voltage so you know for sure and also because it literally only takes 30 seconds to test.

:surfer:

 

[Myrunr2010]

I've got a multimeter, one of the big issues with it though is it's pretty infrequent. I think the only reason I was able to keep better tabs on it last night is because I was driving for 4 hours on dark roads. Of that time it probably only stayed on constantly for maybe 10 minutes over the whole trip, the rest of the time was just random flickers that would happen for a few minutes and then stop for a while. My usual 10-15 minute doesn't cause it to happen, and if it does the only reason I know is bc the abs light will be on (once I turn the car off and then back on the abs light clears).

So I guess all that to say, im not sure how to replicate it in order to tell, and it's usually such a short period of time I'm not sure the quality of my multimeter would be able to detect it.

Make sense or am I just rambling? Do you think one of the obd scanners you're talking about would be able to catch a momentary change?

 

[BrianSD_42]

I agree with you. I think the obd2 would be good because you can leave it on constantly for an hours drive to see if the issue occurs .

BTW just for kicks it would be nice to know what the voltage is with the car turned off and what it is with the car idling.

 

[Myrunr2010]

Is the voltage regulator part of the alternator on our rigs, does anyone know?

 

[Myrunr2010]

Anyone have any opinions on alternators? Are there better ones to get than others? Any upgrades on them? Just looking for some general input.

 

[BrianSD_42]

You may find some of these threads to be useful.

There are a few mentioning similar issues.

Paste this (exactly) into Google:

site:toyota-4Runner.org/3rd-gen-t4rs/ voltage regulator

http://www.toyota-4runner.org/3rd-gen-t4rs/82016-battery-light.html

http://www.toyota-4runner.org/3rd-gen-t4rs/73448-battery-alternator.html

http://www.toyota-4runner.org/3rd-gen-t4rs/180777-what-heck-killing-my-battery-2.html

 

[Myrunr2010]

Well, it appears to of been the voltage regulator. I looked up the cost to just replace the voltage regulator, it was 115, I was able to get a new alternator with lifetime warrenty for 126.

 

[chimpy]

Get a 12V lighter power supply and cut the end off that goes to whatever device the power cord plugged into. Next, get a double banana plug or 2 single banana plugs and solder them to the bare wires on the power cord. The banana plugs will fit in 99% of all multimeters. Plug the newly made cord into the lighter and the other(banana plugs) end into the V and COM ports on the multimeter. Turn the multimeter selector to DC V with the 4runner running and look at the multimeter. This will show the system charging voltage (alternator output). Now turn the multimeter selector to AC V . This will show how much AC V is getting past the rectifier. Best part is you can sit in the driver seat and do all this.

 

[Myrunr2010]

Get a 12V lighter power supply and cut the end off that goes to whatever device the power cord plugged into. Next, get a double banana plug or 2 single banana plugs and solder them to the bare wires on the power cord. The banana plugs will fit in 99% of all multimeters. Plug the newly made cord into the lighter and the other(banana plugs) end into the V and COM ports on the multimeter. Turn the multimeter selector to DC V with the 4runner running and look at the multimeter. This will show the system charging voltage (alternator output). Now turn the multimeter selector to AC V . This will show how much AC V is getting past the rectifier. Best part is you can sit in the driver seat and do all this.

Wow, I'll have to remember this for the future!!!

 

[chimpy]

I did this as a project in my automotive electrical/electronics class in college. I did get an A on this project. Very simple and inexpensive.