Hello DTR's first gen commity,

It's been a number of years since I've posted on here but I recently decided to take on a project and it's basically finished now and I'm trying to button up some of the last loose ends. Truck is a bit of a mutt being a 1/2 ton body on I believe a 91.5 intercooled truck chassis with similar wiring and such. Anyways, as the title says I installed one of the Transpo internal voltage regulators (don't remember the P/N off hand but its the one available on FFS website) and the voltage gauge or ammeter or whatever the factory gauge in the cluster is is inoperable. As soon as the truck is started it jumps to being maxed out on the gauge and stays there but with it off it goes to the 0 position like normal. When the truck had the original VE motor in it my brother (P/O of the truck) said the gauge used to work but when he pulled the engine he left the factory alternator harness on it. Wiring is not my specialty so I guess my biggest question is is it one of the wires by that alternator plug (that is MIA now) by the passenger inner fender that goes back to the voltage gauge? To help clarify The truck has the typical larger blue and green wires, some smaller blue wires, then I believe it was a brown one for something with the A/C that doesn't exist either.

Thanks in advance for any assistance, and my ability to read factory wiring diagrams is atrocious so I apologize for that.

[EDIT] Truck does have factory computer and no spot for CPS in factory harness if that helps!