The voltage regulator circuitry shows to be in the pcm. With everything turned off, is the alternator bat terminal hot?

Answered by JDL (expert)
14,417 answers provided

thanks for the info that is where i thought that iis where it would be. I took a DMM to the b terminal and field terminal and i got my battery reading. then i started it up and got no reading on the dmm at thsoe same terminals.Also after starting it i get check engine light codes 12 (which i have been disconnecting battery alot) and code 41.
iIt is a new alternator and a battery less than 4 months old

Response from badger0269
1 question asked

I'm not sure which terminals, had no voltage with the engine running? B+ to the alternator field comes from the ignition switch. The other field terminal is ground, pulsed by the computer.

Answered by JDL (expert)
14,417 answers provided

i had one wire from dmm connected to the B+ terminal and one cable of the dmm to the field terminal and with vehicle running i no longer got a voltage reading there. Maybe i am missunderstanding how tho check to make sure that the alternator is out putting the proper voltage to the battery.

Response from badger0269
1 question asked

Use separate engine ground, to ground the meter. Test the bat terminal and field terminals one at a time, engine running.

Answered by JDL (expert)
14,417 answers provided

okay i tried that with engine running i got the same voltage at the 2 field terminals and at the b+ terminal it was 12.6 volts+/-. There was no change in the voltage also when i stepped on the gas to increase the rpms.
thanks for all the info you have given me so far

Response from badger0269
1 question asked

If there is no pulse on that one field terminal, it's either the wiring circuit or pcm.

Answered by JDL (expert)
14,417 answers provided

thank you for all your help and time. I will look at all the wiring hope that is where its at.
Once again i really appriciate all you help

Response from badger0269
1 question asked