2002 Cadillac Escalade Ext Repair Question
Mileage: No information provided.
2002 Cadillac Escalade Ext Charging system
2002 Cadillac Escalade Ext V8 All Wheel Drive Automatic 145000 miles
....when I first start my truck, the battery light comes on and the voltage gauge shows 8 or 9 volts. after driving for a few minutes, it goes up to normal 14+ volts and the light goes off. problem does not surface again while driving, only when it is started again......suggestions????
Answer
What kind of condition is the battery, and cable connections in? Start there first, and if everything is o.k. you may need a generator.
Battery is new and cables are fine. Alternator seems to work fine once it starts working. Almost as if it's heat related.
Test at the back of the alt (big wire) with a meter when first started to see if the alt is actually putting out but the gauge is slow to come up or if it isnt charging. Could be a wiring or gauge issue
The alternator is not putting out when first started. I didn't test, but lights are dim, so not guage problem. After about 15 minutes the alternator appears to work, and stays working until next time when car is cooled down.
Sounds liek it may be thealt then, but hteproblem is that the alt is controlled by the PCM, so hopefully it isnt an issue with it.

I'm trying to figure out if it's worth it for me to change the alternator? The belt seems tight, and not slipping, but no measurement for that. I would think, if it was a little lose, when I put a load on, it would take care of that. But, it just seems to take about 15 minutes before the alt kicks in. Now, if it's the PCM, then I would be wasting my money chnaging the alt, right?
An 02 with 145k, an alt wouldnt be out of the question, far more common than the PCM.Usually if the PCM sees low voltage it will set a check engine light.usually ascan tool would be used to see what kind of system voltage the PCM is seeing to determine which it is.I doubt the belt has anything to do with it.
Final comment. Three times now I have started the truck, the voltage gauge is reading around 10V, I give the alternator a rap with a hammer(not hard), and the guage shoort right uo to normal. Whats up with that?
Ah, the old hammer test.....lol sounds like a bad connection in the alt
does a bad connection in the alt, mean i need a new alt..........or a bigger hammer?