NYC 993

I was hoping all you electrical experts could help me out with this one. Here's the situation: 1997 Carrera, driven once a month or so during the winter months and I haven't had it on the trickle charger this year. Kept in a warm garage, except for last night I left it outside and the temp dropped into low 40s. Cranked it up this morning and it was a slow/hard crank but caught on the first try, I did notice that the dash lights seemed dimmer than usual.

Driving along a curvy road and the abs light flashes on, then off, then on again, it's coming on when I'm hard on the gas and then turns off when I back off the gas. Then the stereo starts to fade out, dash lights dim and then the airbag light flashes on, then off. I pull over, turn off stereo and heater fan, dash lights return to normal.

Then on the highway, everytime rpm's stay above 3k rpm the dash lights dim, return to normal when revs drop below.

So what do you guys think? thanks

ljugete

It sounds like it may be the Alternator. Get it checked out ASAP!

I was stuck on the freeway last summer and had to tow her home $$$$. I was driving back from a long trip (fortunately I was w/in 50 miles from home) and the lights went crazy and then the car shut off (pulled to the side of the road). Everything (incl. the hazard lights were dim). I jumped it with no problem, but went off as soon as the starter cables were disconnected! I also replaced my battery with a new Interstate Battery. No problems since then (knock on wood).

Good Luck!

NYC 993

well search is my friend, def looks like a shot alternator so ordered a new one from pelican. fingers crossed the car gets me home from work tonight!

2Many Cars

Do yourself a favor and leave early so you won't need to use your headlights. Also leave the radio and heater fan off. The less draw the better. BTDT.

jimz993

The ABS light turns on because the battery has a low charge/voltage. Try to charge the battery first and the light will turn off.

Dudley

Here is a shot in the dark.
Do you have the RS Pulley update installed?

NYC 993

I don't have the RS pulley, but am thinking about installing that when I replace the alternator I picked up a multimeter and checked the voltage, battery putting out a solid 12.2volts, but when i turned on the car, that dropped to 11V and went downhill from there as I turned on more accessories. Definitely a bad alternator. 56kmiles or 12yrs I guess was enough for it.

Davies

Jay - You MIGHT need a new alternator. But from my experience, your symptoms point to needing a new battery ground strap. Don't bother inspecting it. Just toss and replace. I had the same issues a few years back and that was the culprit.

Garth S

the probability is very good that replacement of the regulator/brush set will cure these issues: it's 10 min to do once the alt is out ... and it must come out in any event.
A brush set is ~$20, such as this one - and is held in with two screws.

cmat

I would first make sure your battery is ok before tearing into the alternator. It needs to be charged properly then tested under load. Take it to a local car parts shop.

2Many Cars

That's actually the whole voltage regulator which is common to a lot of Bosch alternators. When they go bad 99% of the time it's just worn out brushes and at 56K miles it's a bit early for that. When you pull the alternator remove the voltage regulator and compare it to Garth's photo above. The brushes are spring loaded and when the VR is removed they should stick out about like in the photo, or at least pretty close to it. If they don't that could clearly be your problem. If you plan on keeping the car I'd get an alternator rebuild anyway because if the brushes have worn down in just 56K miles then it's probably due to a rough armature and it will happen again. Under normal circumstances they should usually last 100+K miles.

Blaine S

Have any of you checked what your voltage reading is from the OBD-II? I was checking mine last weekend and it ranged from 13.4-13.8 volts on a ScanGauge II. I thought it should be closer to 14.2-14.4 volts.

NYC 993

I'm not electrically adept enough to rebuild the alternator, so just went ahead and ordered a new one, and the battery ground strap is a good idea too. Thanks for all the great ideas.

pchansen1

I'm sorry I wasn't able to post earlier but... I had the same exact problem with my '95 C2. It turned out to be the grounding strap. I know, I know too easy isn't it? For some strange reason the un-shielded grounding strap (battery to chassis) starts to corrode after oh say about a decade and the resistance in the strap goes off the charts. I wouldn't have believed it if I hadn't checked it myself. A $10 replacement was found at the local auto parts store. All my weird electrical problems went away in an instant. Also, try testing your alternator before replacing it. A failing alternator will start to emit an excessive amount of AC voltage. Take your multimeter and switch it to AC volts and take a reading across the battery terminals with the engine running. Anything more than 300 millivolts of AC current and your Alternator diode packs have failed and then you can buy that new alternator. Hope that helps.
Paul

pp000830

This is a long shot. Years ago I had experience where the brushes in the alternator were very worn and at higher RPMs they would stick and lose contact and no charge. Not sure how easy it is to change the brushes but take a look. A good way to chech your charging is to see what the voltage of your system is while running if its over 13 volts your system may be charging but your battery may be suspect. To check the battery have a garage test it for you.