alternator light on

Fly Mach .86 · 08-25-2003, 09:59 PM

Started the car the other day and got a alternator light. The light dims with increased rpms but doesn't go out completely. I'm thinking Voltage Regulator. Any trouble-shooting ideas? (Carbed 73 2.2)
Cheers, Elliot

Tidybuoy · 08-25-2003, 10:31 PM

I had a similar problem a couple of years ago. I don't remember the exact solution but I think that all I did was replace all my fuses with new ones, wire brushed the contact points on the fuse block.

I definately did not have to replace the alternator or the voltage regulator. After I did the above, the alternator light went out completely & it's been fine aor a couple of years now.

I believe that I also replaced one of my relays & cleaned up the rest of them. Also, check your ground strap at the battery & the rear of the transmission.

Also, according to my DR. 914 tech tips book, it states this problem could be either a bad diode in the alternator or bad ground - my case was grounds (undo them & wire brush to nice clean metal).

Vern

brians914 · 08-26-2003, 06:07 AM

I had the same problem last spring. I took it to my local auto electric shop and they rebuilt the alternator, put in a voltage regulator, all for $198.00. I thought that was pretty good. All is fine now.

John Rogers · 08-26-2003, 08:23 AM

I'd check the following in this order: first the belt tension to make sure it is tight, second the ground connections, third the wires to/from the batt and connectors and replace if they are more than 4 or 5 years old, fourth all the fuses and clean the contacts on the electrical panel, fifth the batt for load handling ability, sixth the alternator and voltage regulator for output and replace if necessary. If the alt is bad I'd only use a Bosch replacement and use a new regulator at the same time. The alt can be removed and installed with the engine in the car but it is a small pain. You can also go with the high output VW Bus/camper alt but you need the bus wire harness from the alt to the replay board. Good luck.

ws91420 · 08-26-2003, 09:17 PM

When I had this problem like yours. Ligh on at low RPM and fades at higher RPM it was just the brushes in the alt. replaced those and no other problem. MY .02 worth

Will98D · 08-27-2003, 05:19 AM

Ditto the above wrt connections, etc. You can see if it is the regulator by being it yourself for a few seconds. The regulator controls the voltage by supplying or removing 12V to-from the Field circuit in the alternator. Figure out which of the three wires to the regulator is Field, put a jumper in there (but not on 12V), start the car and then momentarily connect the other end of the jumper to a 12V source. If the light goes right out (or of you have a volt meter you see it climbing quickly) then it's the regulator OR the 12V source that the regulator uses (also one of the 3 wires in the pigtail that you have to check; I think it connects to the D+ terminal on the alternator itself). If not one of those things you'll have to have the alternator checked. Also, only make that connection MOMENTARILY, just long enough to see the light go out or voltage rise to 13.5V, otherwise the voltage can climb above 15V and you could start to damage things.

Fly Mach .86 · 08-27-2003, 12:23 PM

Thanks for all the help. I think I narrowed it down to the voltage regulator. I dropped if off at the people who built the engine (Fat Performance Orange California) and they are adjusting the Weber carbs and valves and they said they would check out the alt. light for me. It seems the 44 idf carbs are a bit much for 2.2 so they will use smaller venturies. Thanks again everyone for all the great trouble shooting advice.
Cheers, Elliot

Dave at Pelican Parts · Dave at Pelican Parts's Garage

I would'a replaced fuse #9 and cleaned up the metal "fingers" that hold it. Worked for me...

--DD

Fly Mach .86 · 08-27-2003, 03:25 PM

Thanks Dave,
Actually I replaced all the fuses and cleaned all the fingers that hold them. The guy at Fat Performance was fairly sure the alternator worked because it was charging when the engine was on the Dyno. About the only thing leaft is the volt. reg.
Speaking of the Dyno. They had a 2.5 Toyota engine running on the Dyno while I was there. They were running it flat out and in was ear plug time. (Really really loud!) They guy running it told me it was producing 300 HP!
Cheers, Elliot