hey guys, so i am having a bit of an issue. I had a stereo that i put in my 87 4runner and it worked just fine. Then someone decided that they liked what i had and didnt want to work to get it. So they stole my 4runner and radio. I got it back and to my surprise they only took the radio, sub, amp, shift knob, and front blinkers. But not my brand new swampers? anyways i was trying to install a new radio today and everything seems fine power wise. both power wires on the harness are giving me 12.2 volts, until i plug in the stereo then one drops to like 4 volts and the radio will not power on in any way not even backlight. It's driving me crazy and i cant figure it out. Anyone got any idea?

 

I had a issue like this that about drove me crazy.

It turned out the plug was just corroded enough to not work plug in but worked fine when testing with the meter.

Some after market units have a ground that is not in the harness . Look to see you have a good ground