Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!
Check the ROOM fuse (hot at all times) in the Joint Box under the driver's side of instrument panel. Load test it with a headlight bulb. If it's bright there, then check it at the computer (Blue with Red tracer). The key can be off, you can back probe or front probe it, and make sure the terminals look good and tight.
I found the room fuse. Will load test the wires. Let you know what is found. I removed the Computer in the meantime. Found what looks like corrosion inside. But I will continue testing before ruling out computer. I have a test computer to try in it also.
