dj44

About a month ago, started to get flickering lights, slowing blower motor, etc....eventually ALT/BATT light on dash came on - replaced alternator and still have the same problem. New alt and battery both test OK multiple times by AAA and parts stores. Problem is not related to bumps, potholes, etc...and either only happens or is only noticeable just after stopping at stop signs, traffic lights, etc....

Also checked and replaced battery cable bolts. Now driving around afraid that this alternator is eventually going to die and leave me stranded and getting towed and then paying a fortune to a repair shop for what I already did - again.

This all started after I was testing the cooling fan motor with lead/alligator clip wires and they touched (I know - I stupidly was sure that connecting the battery ends first would not be a problem but the wind had other ideas). So my question is - is the only thing this could be - a failing voltage regulator in the "new" (reman) alternator? Or is it the PCM/computer? It is an intermittent problem so every place I take it can't really do anything and that has left me stressed. Especially since I damn near killed myself trying to get the belt back on after putting in the new alternator. I don't think I can do it again.

Thanks for any ideas.

tech2

what year, engine, model etc

if the battery light is on, a dtc is set in the bcm. get the dtc read and post it here.

Ladmarines

I have seen that on my suburban the Batt guadge will go from like 14 to 10 while driving some times.

cleveland63b

have you checked the voltage at the battery idling when the light is on?

dj44

2001 Cavalier 5-speed manual 2.2. No codes being thrown. No dash light on with this current problem. The voltage problem with the old/original ALT was when it was under load as in starting in low gear, going uphill, etc.....but this new problem (also a voltage drop causing lights to dim, fans to slow, etc....) is not under those conditions. Instead, it happens or at least I can *tell* it is happening or it is at its worst just after stopping at a stop sign, red light, etc....(pressing on brake is unrelated). Seems totally random, doesn't always happen and the severity of it isn't always the same. Had both the battery and alternator checked several times and they keep telling me both are OK. But the problem is not happening when they are being tested and I can't test them when the problem is happening. Does not behave like a loose connection since jarring, bumps, movement does not affect/cause the problem and just the opposite - it happens when nothing is moving and the car is sitting still. But if I just start it up and let it sit and idle, the problem does not ever happen.

You can see why it is troubling, annoying and I am worried about it.

tech2

not sure what your are experiencing.

lighting systems are all controlled by the bcm so they set body codes. body codes will not illuminate the ses light. the codes cannot be read with a code reader. a full function scan tool must be used.


a common corrosion problem can be found under the battery tray....this is a wiring harness that leads to the headlamps

dj44

Could it be a damaged/failing belt tensioner? No belt noises, though. Could the PCM/BCM/computer have been damaged by the touching of the two battery wires together as I described in my first post? Sure seems too much of a coincidence to have never had a problem like this for 15 years then to have the original ALT die within days of that spark/wire incident and now this. I guess a trip to a Chevy or GM dealer is required for this scan? Any idea how much that'd cost - just for the scan and info and nothing else. At least then I might have my curiosity satisfied.

Thank