I have a 1994 PSD and the oil pressure, temp, battery, and fuel gauges are acting up. When the gauges act up i can unplug and plug up a box under my dash that is my remote keyless module and the gauges will start working normal till i turn my radio on and they will start acting up again. Expecially when the bass hits on the radio the gauges will bounce. Someone told me that it could be my GEM (Generic Electronic Module) but i have no idea where the GEM would be plus I dont know if that is really what is wrong with my gauges. Any help would be great.
Thank you

Check your wiring, especially on your aftermarket devices (radio, keyless entry, etc.). Look for scotchlocks and butt connectors, they are notorious for going bad. If the power source for these devices were tapped into your gauge wiring, a bad groud wire (connection) may cause them to ground through your gauges and give you goofy readings. It may be overkill and more work but I prefer to solder and seal electrical connections. Hope this helps, good luck.

I have thought about that but before i get to involved in tracking my wires i and connections i like to find my GEM like it works some days they will work without a problem then it is like something doesn't reset, cause then they will just all a once they will act up. Has anybody ever here of the GEM and know where it is located. Thank you

I've never heard of a GEM.
Just two days ago I fixed a problem with my aftermarket gauges. I wired them in a hurry a few years ago and used mechanical connectors. I tied the backlighting into my dash lights so they could be dimmed. A few months ago, the gauges started acting funny. I could adjust my exhaust temperature by dimming my dash lights. I soldered and sealed with liquid tape and electrical tape. Problem solved.

Well the way that i feel that if i dont get the gauges problem worked out i thought about running new hot, ground, and sender wires to the sending units. It is just irritating cause i just bought the truck about 4 months ago with 102000 miles and i have been working with this problem since i owned it. It came from Ohio so it was in salt country the frame just has surface rust but still solid. It sounds like it has to be a simple problem cause how the gauges acts at times.