Power Antenna Relay, 1990 Toyota Celica

Hi All, I have a 1990 Toyota Celica GTS and my power antenna does not go up anymore. I replaced the plastic rod and check the motor and it's fine. I took the unit off from the car and I replaced the rod and apply 12 vdc only to the motor to see if it works. the antenna goes up, reverse the polarity the antenna goes down. when I put the unit back in and I made sure the antenna is extended so I can listen to my radio. I tuned on my head unit and turned it on, few hours after my antenna still extended even the radio and the engine is totally off. when I get back to my car the next day my antenna was down even though I have not turn my engine or radio on. so for curiosity I disconnect the wiring harness and apply 12v again to the motor only to extend the antenna when I turn off my head unit the antenna did not go down at all. I can not figure it out when does it go down. My question now is there a way to over ride the original power antenna relay and make my own relay to do the job? Thanks in advance

This was 30+ years ago but I got caught with something like your are having and I "think" there were 2 power antenna wires out of the harness that connected to the radio. One was to get it to go up and then the second one needed to be grounded when the radio was off to get it to go down ?. Maybe some of the "old school" people will remember this and have more info. Jim1968 Chevy II Nova Garage Find 2012

1973 Nova Custom

1974 Spirit of America Nova

1973 Nova Pro-Street

I bought this car used and no radio unit at all. they disconnected all the wires so I was left from scratch. I remembered hooking up my new radio harness blue only to red/white of the car radio harness which is supposed to be for the power antenna signal. I believe.

So the car had loose wires you connected to or did they leave the factory plugs still intact and you then plugged in a harness adaptor that wired to your new radio ?. Metra has a harness adaptor and you can see that there are two blue wires off of the plug and both need to be powered off of the power antenna lead on the radio. If the factory plug was cut off, then maybe you have an unused wire out of the car that is not connected to anything and this is the second antenna activation wire. Jim1968 Chevy II Nova Garage Find 2012

1973 Nova Custom

1974 Spirit of America Nova

1973 Nova Pro-Street

Hi Jim do you happened to kniw what color is from the wiring harness that I will be looking for. I still have few more wires from my new NA3600M Nakamichi deck that are not connected at all. Thanks

I did not see any color called out on a radio wiring diagram I found but the picture I saw shows a terminal labeled ANT which should show 12V when the radio is on and goes dead when the radio is switched off or the ignition is turned off with the radio on. This would be to activate a power antenna. Picture of the back of the radio I saw: https://www.wavetech.co.nz/static/images/cache/nakamichi-na3600m/3/1000-600/wt/2896007849-1679630060-1613678365.jpg Chances are you will have unused wires depending on the installation. Just cap them off so they cannot short to anything. On the above post of mine, on a harness adaptor, the antenna activation wire is the blue wire and you can see how it's jumpered also to connect to a second wire in the cars harness. Jim1968 Chevy II Nova Garage Find 2012

1973 Nova Custom

1974 Spirit of America Nova

1973 Nova Pro-Street