I'll say thanks in advance because im really at a loss for what's going on with my 97 1500 5.9.

so i changed my thermostat two days ago because i live in montana and its starting to get cold and you want real good heat here. i did disconnect the battery before i did anything. i found out last time i did my thermostat that its way easier to get access to the waterneck if you pull the alternator off. anyways got all done and put it all back together with no leaks
well then i noticed i was only reading 10 volts and the gen light was on... i got my alt. tested and it passed with flying colors but my multimeter said it was putting out 34v waaaayyy to high. you can't really mess up the wiring, but i double checked everything. i go to turn the key again and the alt fuse pops and then i have no lights or anything. that surge somehow managed to fry my battery....if you put a charger on it things work but the second you take it off everything goes out. if you touch the charger on the terminals a couple of times the lights will stay on but as soon as you turn the key everything is out again

i work in the oilfield here... in about 2-3 weeks it will be freezing if anyone can help it would be greatly appreciated!



she has 260,000 on the original 46re and 5.9... still has plenty of power and shifts smoother than my buddy's 02 silverado with 200,000

i love this truck!!!

 

Bad ground somewhere. Recheck battery connections, I bet one is loose/corroded.

If it worked before, and doesn't work now..... probably just a poor connection. Recheck all wiring for the alt, and also check wire routing. Make sure something didn't get pinched somewhere.

If all else fails.... voltage regulator is in the PCM.... only way to fix it is replacement. An alternative would be installing an external regulator, but, that tends to leave the CEL on, whining about the charging system.

Welcome to DF!

 

If your battery is putting out 34 volts the internal voltage regulator is bad, and the alternator needs to be replaced. I had the internal voltage regulator in an alternator go bad once, and when I was able to stop and open the hood the battery was boiling.

I ended up having to replace the alternator and the battery.

 

Regulator is in the PCM, not the alternator.

 

thanks for the quick response

found a bad ground and the truck starts again

does anyone know how to wire in a generic voltage regulator to avoid a pricey pcm swap

 

I guess im used to dealing with chevy alternators, were the voltage regulator is built into the alternator it self.

 

This will give you what you need

No CEL, and one helluva lot cheaper than a PCM.

 

wow, quick start is still around. I think I will get a kit just to have in case. Fair price too.