Voltage regulator is in the PCM. Start with the basics. Check batteries. Load test alt - can be done on the truck. The check for codes.....PCM controls the output of the alt.

 

Thanks I will be doing this first thing AM!

 

This same thing happened to me.

Check the connections on your grid heaters for ANY play at all.

I was so freakin' happy when I finally found the gremlin.

 

I had the truck checked today and it turned out that my alternator is shot! Thank you guys for all the good imput!!

Chris

 

Chris, Check out http://www.mean-green.com/products/alternator.html for a replacement.

 

shoot if I wasn't in need of one like right now that would have been the way to go as is I bought one from NAPA for $178. I'm sure it will quit me in a few weeks knowing my luck lately

I sent you a PM

 

I don't believe there is any charing function in the alternator. The charging is supplied by the PCM or ECM (on my 97 its just a PCM...not sure what your ECM does tho). The alternator just has windings and the diode rectifiers.

This is why most auto parts shops that test your alternator say the regulator in your alternator is not functioning...duh...there is none. Be carefull of the average parts guys mis-diagnosing your alternator as bad.

 

so how would I know if it is a pcm or ecm??

 

Hey Dave Miller............... I decided to check further into what you were saying about the ECM and what I found out agrees with you, there is no regulator in the alternator the ECM controls that so after talking with some electrical shops they all said that I should recheck the Bats. and put a load test to it since most of the "part store gurus" only check voltage and low and behold one of the bats. under load was shot. put a new B\bat. in and everything is working good again.

So thanks Dave you saved me $178 on a alternator and $700+ on a ECM

If you are ever up in Montana check me up and I'll buy you a beer!!