my charging system quit working, so i then put a rebuilt alternator in and that dint fix it. then come to find out the voltage regulator on my truck is built into the pcm...(stupid)...so i bypassed the pcm by wiring up a new mopar external voltage regulator, now its charging rate is around 15.5 to 16 volts and is not steady. the gauge and running lights bounce up and down. what is the problem?

 

Sounds like a bad ground somewhere. Kinda doing the same thing a sulfated battery would cause. The regulator increases alternator voltage trying to push the current through a bad connection. Should charge around 13.7-14 sumthing. Shouldn't be higher than 14.6 tho.


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Usually comes down to 2 possibilities. The first is bad connections, usually grounds. There are a lot of both in the circuit. The second is how the external regulator was wired in. You need to completely disconnect the 2 wires from the pcm. Best place is at the pcm. Then use the 2 wires to the external. MAKE SURE THE EXTERNAL HAS A GOOD GROUND. Sand the pant off around the screw holes so it gets a solid contact.

 

I had a 93 once that done the same thing 15.5 to 16 will not hurt anything I drove mine for a year like that and then I got rid of it and it never bothered anything but the lights do get kind of anoying.On my 92 I had the same problem a few months ago with the bouncing charge but my regulater was fine but it wound up being a bad fuseable link not making good connection after I changed it I havent had anymore problems I also replaced grounds and it didnt help.I dont know if this will help or not but I hope it does good luck.

 

i've ran into a bad regulator causing these issues too. if i remember correctly i ordered a mopar performance one from summit racing and it solved the advance auto parts brand issues.

 

You have a GOOD ground at the regulator?

 

I'm gonna try the ground at the regulator and ill get to ya thanks everyone

 

Any update?

 

I tried a ground from the regulator to the engine block and still had the same results. I dont know what to do

 

Did u check the fuseable link its the little white one that is by its self.