My battery light has been turning on. It appears to be directly related to the rpms of the engine. Once I get over 4000 rpms the battery light comes on. If I upshift and lower the rpms the battery light goes off. The opposite happens when I downshift (i.e. the light comes on). I am thinking in may be the belt or the voltage regulator. Any ides?

 

Have you taken apart your dash recently?

Maybe you swapped the connectors between that and the shift light

It does sound like maybe the alternator belt is slipping.

 

It is an early 944, so I am not sure if those had a shift light. And yes I have taken the dash apart ( as with everything else on the car). I have not had any problem with the battery so I am not too worried about it.

Maybe just use it as a shift light?

 

I'm not entirely sure... but I am pretty sure they do. The shift light is the only part of the Tach on my early car that DOES work.


.. I think. I havnt driven it in a while

 

Earlies with the "MPG" gauge in the tach also have a shift light. No MPG gauge, no shift light.

 

I have had 2 83 and both had the mpg in the tach. neither of them had a shift light. I wonder if the bulb was just blown out. where exactly would it be on the tach?

 

The upshift light is non-replaceable, it's soldered right to the board inside on early tachs. I wanted to delete mine, but you really can't without major surgery.

 

Replaced the voltage regulator and belt today. No change in the battery light turning on or off.

I have noticed that the light comes on at a variety of different rpms and will turn off at different rpms. Does the shift light change around like that? I do have the mpg, but have never seen a shift light.

 

Does the voltage light go on/off, or does it glow at different RPMs?

Our chumpcar had this issue, and we basically circumvented the exciter wire (tiny blue wire on back of the alternator) after verifying the battery had the proper reading with the car on.

 

The light turns on between 4000 and 5000 rpms. It stays on until I get back to around 3000 rpms. If I am hammering on it pretty good, it will stay on even when I upshift.

What did you do to circumvent the wire?

 

Ours was a slightly different problem - it was brightly on at all RPMs, brighter when the motor revs.

I think we wired it back onto the bigger wire in the system.

 

Could be the brushes are marginal in the alternator, get thrown back at high RPM.

 

Alternator failed today at the track. I guess that solves the mystery!

 

I have the one out of my early '85 (5 rib pulley), but I bet shipping would suck. Le me know if you want it, since I'll be at the shop tomorrow and can grab it easily.

 

Thanks for the offer. I have a line on a remanufactured one that I can get next day.

Anybody know the difference between a Bosch and a USA Industries remanufacture?