Alternator idiot light won't go out

[syncromike]

Hello, I have a 91 Vanagon and added GW aux battery kit. A couple weeks after adding the aux battery the alternator light started coming on. Intermittent at first but then became steady.

I found that the voltage at the alternator while engine was revving was only 12.2V. Pulling the voltage regulator found that the brushes were done.

I replaced the regulator/brushes and now I have 13.5V at the alternator when engine is running and 13.4V at the starting battery, but the alternator LED idiot light always stays on. I drove all weekend monitoring voltage and didn't have any issues, both batteries are staying charged from the alternator.

Is there a fuse or anything between the battery and the LED that could have blown when I was working on it???? Why would it still be lit?

TIA,

Mike
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'91 Syncro w/ Country Homes PopTop

[Vanagon Nut]

First thing I'd check is if blue wire at alternator is properly connected. If ok.....

If brushes and/or reg on alternator weren't working, could this condition have damaged the battery isolator that came the the GW kit?

Did you measure voltage of aux. battery before this issue happened? Am curious if it's simply holding the charge it had prior to the battery light issue. e.g. if battery isolator fails open, aux. battery not used, it holds its charge.

On my Westy, the battery isolator needs to close (connect battery to power from alternator) before the alternator light will go off.

Are grounds ok? e.g. does battery isolator have a good quality ground?

Neil.
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1981 VanaJetta 2.0 Westy "Jaco"
1988 Westy To Be Named! :^)

Vanagon VAG GAS engine swap Google Group:
https://groups.google.com/group/vanagons-with-vw-i...irect=true

My Air Cooled Vanagon to 15º Jetta ABA swap pages:
https://sites.google.com/site/tubaneil2/15degreeengineconversion

[syncromike]

[greenbrier62]

I have the same issue as the OP; batt./Alt. light is on all the time. I also have the GW aux. battery kit installed and I have changed the voltage regulator. Here's my story:

I installed the GW aux. battery wiring harness about five months ago and everything worked fine. During a week in July I changed out all of my coolant hoses etc. and when I went to start her up, no go...So I charged the battery and off we went. That's when I noticed that the light was not going out. The click behind the drivers seat is not clicking either. (I use to hear a click after I reved up the engine after start up. I'm thinking it was something that activated that then allowed the alternator to charge the batteries?) After reading the post(s), it seemed I needed to try the less expensive fix, and replace the voltage regulator...light is still on. I've charged both batteries to full capacity since the regulator install, and in fact I've installed the proper start up battery (PO had a larger batt. installed). I have not checked the voltage coming out of / off the alternator, but if it is off, then I'll probably need a new alternator? As I understand it, the light comes on when the battery(s) has a higher voltage then the alternator. Is that correct? Also, does the light (or system) read voltage from both batteries now that the aux. batt. is installed?

Thanks in advance Samba volks!
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1987 Vanagon camper
2005 VW Passat TDI
1972 Chevy P/U custom
1962 Chevy Greenbrier

[Corwyn]

I had the same issue: with a second battery and solenoid switch, I had to rev the engine up to 3000 rpm to get the solenoid to click. I replaced the wire from the alternator, going up one gauge and that seemed to fix it. Now the solenoid switches upon startup.
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'90 White Westy ("Needy")
Automatic, 2.2 WBX
Olympia, Washington USA

"If anything's" gonna happen, it's gonna happen out there"
~ Captain Ron ~

[crazyvwvanman]

It is a very simple system and does not work how you stated.

The dash alternator light is mainly intended to tell you if the alternator is turning. It does not "read" any batteries.

The alternator has a small blue wire connecting to it that comes from the alt warning led on the dash. Your problem is most likely caused by a bad connection on the blue wire or the blue wire may be broken or may have fallen off at the alternator end. Look at the alternator and check the small blue wire to see if it is connected and solid looking at the connection.

The alternator shares a belt with the water pump. The alternator warning light thus acts as a warning if the critical belt should break. If the water pump suddenly stops turning the engine will cook fast. That is why it is critical to have a working alternator warning light.

The alternator warning light should be on every time the key is turned on, and go out after the engine is running.

Mark

[greenbrier62]

Thanks...I'll check the blue wire. Where does the other end go? Does it run the length of the vehicle and connect up front? I ask, because I've replaced the end that connects to the alternator and that means either the connection is still bad with the alternator or the wire is cut somewhere between here and there...
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1987 Vanagon camper
2005 VW Passat TDI
1972 Chevy P/U custom
1962 Chevy Greenbrier

[crazyvwvanman]

The blue wire connects from the alternator to the dash. There are some junctions along the way. Problems with the blue wire are almost always in the engine compartment. Most often at the end where it is supposed to attach to the alternator. The end can come loose on the alternator, or the crimp can be bad, or the wire can break off, or the wire can break inside the blue insulation where it can't be seen..... Sometimes people get confused and hook the blue wire to the wrong place on the alternator and then the light stays on. The other place that sometimes causes a problem is inside the engine compartment wiring box. In there you will find a single pin connector where the blue wire segment from the alternator joins the blue wire that runs in the main vehicle harness up to the front.


This is all related to my general disapproval of the GoWesty aux battery kits that make use of the blue wire circuit to activate their large solenoid relay. The large solenoid relay puts a much heavier current draw on the alternator blue wire than VW ever did. The extra heavy draw makes it more likely that the alternator warning light circuit will behave badly. It is not always the direct fault of their relay but their relay can aggravate the symptom of a weak or aged connection. It is easy to install their kit in most Westys without causing a bigger load on the blue wire but that is not how their directions say to do it.

Mark

[Altoona]

[crazyvwvanman]

That is good to hear. The ones I had seen a while back were not that way. Maybe they do listen to feedback. What about the kits they sell for vans without fridge relays? Do you know how they currently say to control those?

Mark

[Altoona]

[insyncro]

GW changed the kit after having issues with it as Mark describes.