I am having voltage regulator issues on my 91. My Guage shows pegged @ 18 volts nearly all the time I am on the road. I have read in the stickies about converting to an internal regulator and would like to attempt it. Question is though what to do with the wire plug in from the external regulator? Does it just become not used at that point? Any help or answers are greatly appreciated.

 

have you checked volts at the battery? 18 would fry your lighting initially, with everything else following, 14.5 is max.

 

I'm with sooty. 18V will burn things out, and blow the top off the battery. Hopefully it's just a bad indication (gauge). Check the actual voltage at the battery.

 

18V! Yikes! I swear by the regulators that are still available through Mopar. Those $19.95 units at places like SlaughtoZone are garbage.

 

This might help. https://www.dieseltruckresource.com/...-101-a-307266/

 

Put your regulator on a relay first. That should do the trick. External voltage regulator rewiring write up with a few pics - Dodge Cummins Diesel Forum

 

Thanks for the info. It sure is nice to be able to ask questions and have responses to help a guy out. Thanks again...

 

Just to clarify the comments. If either the ground or the feed (sample) voltage to the VR is weak, it will overcharge. A bypass ground lead to the body solves the ground issue. A relay feeding battery voltage driven by key on solves the sample voltage issue.

 

Thanks for the info. I installed a relay as in the response from peckens. Solved my problem I believe.

 

Everything else is still running through a bad ignition switch. You should change it.

 

Like ^^^^ says.

 

Could you just run a power wire from the battery to the voltage regulator just to test this and see if it's the problem before wording in a regulator.....

 

For those of us that have been at this for a long time, "hot wiring" a system to bypass suspected components including wiring and fuses is a standard troubleshooting technique. Don't do it without a wiring diagram though, you may fry something else.