I installed a radio in a 1990 suzuki sidekick. I had to hard-wire it because no access to aftermarket harness. The radio works fine until the headlights/taillights get turned on. Then, it pops the tail/dome 15 amp fuse and the switched power to the radio goes out. I put it up to a 20 amp fuse and it still popped the second you turn on the head lights. I tested all the wires with a DMM before installing. The switched wire had an inline 7-amp glass fuse on the factory radio. I clipped that off. Any suggestions??
Try testing the wire you have wired to the accessory and to the +12V wire for a ground when the car is both on and off. Do this with the radio unhooked and with a new fuse in. I am going to guess that you will find that one of the wires is a ground at some point. This is because its an illumination wire and not the ACC or 12V wire.
Don't connect the dimmer and/or illumination wires, just tape them off to prevent contact back behind the dash. If connected they will usually do more harm than good.
Then, make sure that you have a good +12 volts constant, +12 volts switched, and ground connection. Verify the proper ground connection by turning on the headlights while testing. Sometimes the dimmer or illumination wire will work as a ground up until you turn the lights on, so you will know right away if your ground is correct or not. The correct ground will always act the same regardless of whether or not the car is turned on and/or the headlights are turned on
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Ethan
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"Patience, persistence, and perspiration make an unbeatable combination for success"
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