First of all I would like to thank everyone who has helped me with my auto problems and a thanks in advance to anyone who has a solution to my new problem. This forum is great and I have learned alot from reading the Q&A's.
My new problem is with the same vehicle 1998 Cadillac STS 130,000 miles.
the car has been running fantastic since the my last post untill a couple of weeks ago my alternator went out. took it to a GM dealership they told me it would be $1200.00 for new alternator with labor. The local auto parts strore ordered me one for $240.00 it took a week to order and I put it in myself.
this is my only car and I had to drive it to get to work so I had to charge the battery everynight. I receved the new one installed it and it was charging but only to 12 volts with the engine running. I brought the battery in to have it checked and was bad from the past weeks abuse of charging/discharging. So I got a brand new one.Still the new battery was only charging to 12 volts. The parts strore thought that the new alternator was bad and ordered me a new one. Now the new one is doing the same thing. 12 volts. occasionally it will read 12.4 but never higher. I removed the battery while the car was running and the meter read 12 volts. I can drive around town all day with the lights radio AC on and the voltage never drops or the battery dosent go dead. The battery should be charging to 13-14 volts running right? also I dont know if it has anything to do with it but the outside temp thermometer stopped working and is the only trouble code that pops up. I have checked all fuses and they are ok.
What could this be?
Thank you in advance.

 

the ALTERNATOR should be charging from 13.5vdc to 14vdc. where i am, parts stores
like Kragen, Cheif Auto, etc, will bench test the alternator and gotta tell you, Sears Auto aint
bad either on such things. is yours water cooled?

there is no point on trying to see what's wrong until you know it is charging well.
if it works ok, look at the regulator?

a week to order in Seattle?
call around.

http://www.partsamerica.com/ProductL...For=Alternator

http://replacement.car-stuff.com/par...howdc=true#top

 

thanks for the speedy reply. Im on the second new alternator and still getting 12 volts. I bought them at schucks a company related to kragen auto parts. They were the fastest to get it, even the dealership was a week out. It is watercooled and is why it could not be tested.

 

Is the regulator in the alternator? if not where is it located on the car. I have read the manual and it does not cover the charging system. just the removal and replace instructions.

 

also I forgot to write that when I had to charge it everynight I used a fast charger and did not disconnect the battery from the car. I found out later thatit could damage the charging system. If so what else could it damage besides the alternator?

 

charging in such a way is a gamble to the car's electronics, all of them.

 

Thanks Stealth, I was driving it today and noticed the voltage jumped from 12.1 to 13.3 volts a couple times then the battery light came on and dropped back to 12.1. I checked the connections and they all seem clean and tight.
Does anyone know what may be wrong and where to look.