Electrical 1991 LX 5.0, radio wiring help, ECU swap


Jun 7, 2018
Dublin, OH
Hi, I am new to the forum and recently did a 347 swap into my '91 fox, and when doing so, I replaced the ECU with a Holley Hp EFI system. I have the car running and driving, but the radio does not turn on. I believe the radio got its power from the old ECU through its system of big red wires that all join together. I would like to know if anyone has had this issue already before I start digging around and cutting up wires. Any help is appreciated, it is an aftermarket radio that was from Crutchfield so it came with the necessary harness for direct fir into the factory harness. Thank you.
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General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
polk county florida
I believe the hot wire for the radio is in the key on side, nothing to do with the ecu. Checked the fuse? See if you have power at the fuse box of the radio.
for some wiring diagrams: veryuseful.com
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Put lubricant all over the balls
Mod Dude
Feb 18, 2001
Radio wiring is basic, and not through the ECU

Red wire is ignition ON, hot
Yellow wire is constant 12V from battery
Black is ground.

Hook those three up and you have a radio. Then you just need to wire to the speakers
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