Questioni have a pioneer head unit (brand new) and the aftermarket plug for the car, wired the 2 harness's together, did the old plug in to deck, plug into the car, and the deck wont turn on. confused i look it all over and still nothing. so i take the deck and go to my truck, wire it up pos, neg and ign, turn the key in my truck and the deck works fine.
how come the deck wont work in the tercel, i have the proper adapter harness and the deck is brand new, and its wired together correctly.
thanks for your help
Dave
AnswerHi David,
The first step would be to check the fuses in the Tercel. There will be two fuses to check: the "cig/radio" fuse in the driver's side fuse box, and the "dome" fuse in the engine compartment fuse box. If either fuse is blown, the radio won't work. Nine times out of ten, a head unit power problem is caused by a blown fuse.
If the fuses test good, then you'll need to test the wiring behind the head unit with a multimeter. If the ground wire is connected through the adapter harness, make sure there's a matching ground wire in the factory radio plug; some vehicles are designed so that the radio is grounded through the mounting brackets, so there may not be a ground wire in the radio plug. Otherwise, the radio power wires are red and yellow. The yellow wire should test with 12 volts at all times, regardless of the key position; the red wire should show 12 volts with the key in the "Acc" or "Run" positions. If either wire doesn't have power, but the fuses are good, you might be able to run a new wire to an alternate voltage source at the fuse box or ignition wiring.
Hope this helps!
Brian
