stock amp wiring

[3.0 GT]

i have an 89 supra and i noticed under the passenger seat was an amp. it says fujitsu ten limited um-173 and has a part number 86280-14240. well before i knew it was there i wanted to hook up the radio, not stock but came with car and it wasnt hooked up. in the dash behind the radio i saw two plugs that were plugged into each other and another connector by itself. i found a wiring diagram and unplugged the connectors and snipped the mail ends and hooked them up to my radio and it worked fine. then i found the amp and noticed it had the same plugs. so i went behind the radio and disconnected my connections and reatached the male connectors and plugged it in. so now i have all the speaker wires, ignition, positive and negative power, antenna, etc. split between two connectors which runs to the amp then another different connector as stated above back behind the radio. i cut the connector off and figured out that the grey wire is negative and the blue wire was positive. but i cant figure out which wire is ignition. any help would be awesome or a wiring diagram because i dont know which wire it is thanks!!!!!

 

[Who]

There is a 99% chance that the factory amp under the seat does not work. My factory amp stopped working. I bought a used one and it stopped working after a week. Long story short. Forget the factory amp. Now the good news. You can bypass the amp easily. The two plugs plugged together take the signal to the amp under the seat and back behind the dash. When you disconnect them from each other one of the plugs goes into the back of your radio. Unplug the the two plugs that were plugged together behind the dash and get yourself a toyota radio that is self amplified with no external amp. Its plug and play after that. No need to cut any wires either. If you go after market there are plenty of adapters. Toyota kept the same plug for 20+ years. The color of the wires can vary from year to year so it gets tricky trying to sort out the colors. Just connect all the plugs and wires back together and start from the beginning.

Check out this link here on SM it might help.

Your topic might be moved because it deals with audio. You can find the audio topic as a sub forum of General MKIII