1985 Supra wiring

I tried to install a new radio in my 1985 Celica Supra, but now pushing the horn button turns on the parking lights, and the driving lights won’t pop up except when only the parking lights are on and the bright lights are flashed. Please help

Did you cut into wires, or use an adapter plug to use the factory wiring? I’m assuming you tried to tap into some wiring under the dash, and just check to see if it was a ‘hot’. Now, the electronics are freaking out. You’ll need to un-do all the work you did if you hope to have the car behave correctly.

Best Buy, and stereo installation shops, have the adapters. They simplify the installation considerably. Just cutting and splicing wires on a newer car can damage some very expensive electronics. Be glad yours is an oldie.