I recently did an engine swap an I have no gauges on the instrument cluster of course. Currently as of right now I am not using any type of wiring harness or computer on the truck. Im just using gauges direct to the engine to monitor everything. Im still using the stock 98 dodge dash however to. My question is, how do I get the fuel gauge to work? Does the fuel pump send a signal to the pcm telling the amount of gas? Or does the fuel pump send the signal straight to the dash for gas levels? I still have my stock wiring harness and stock computer. I was thinking if, would I be able to wire something up through the junction block on the fuse compartment? I havent tried putting the junction block on the fuse compartment back together. Might be worth a try?

 

Even the friggin fuel gauge goes thru the PCM.

Problem is, all your gauges are driven by the PCM, via the central timer module. Only way to convince the stock gauges to work, is to hook up the PCM, and give it the inputs it wants. Otherwise, your only choice is to custom wire whatever gauges you want.