Car Stereo Issues

[Foster48x]

I think my wiring is possessed (again). A few months ago I installed a Kenwood KDC-MP242 into my 80 FI. Worked great until recently now the radio turns itself on and off while the engine is running. Funny thing is it only turns off if you depress the gas pedal while the car is running and will turn right back on when you hit the break pedal.

Here's where I'm at with troubleshooting the problem.
The red power wire is running into the cars radio wiring harness via the brown wire on the harness.
The yellow wire is running through the red wire on the harness and keeping the memory on the radio when turned off.
I thought it might be a ground or ground loop issue so I grounded the radio directly to the chassis. No luck.
Radio works fine when the key is in the int position with just electrical power and the engine off.
Its got a removable face plate which doesn't seem to be the problem. Contacts are clean and the face secured.
There's no wiring or plugs that I can see getting hung up on the brake or gas pedal.

According to the 80FI wiring diagram the brown wire from the cars radio wiring harness runs through the headlight switch and then goes to the fuse box and ends up at the ignition. Is the car just drawing too much amperage while its throttled up to keep power to the radio? Should I run power directly to a wire off the ignition and if so which one? Maybe a ground issue somewhere else?

What do you guys/gals think? And please don't tell me to remove the radio and listen to the beautiful exhaust note I need my satellite radio back!

Rick

[azygoustoyou]

It sounds like you have ghosts Does the knob move when it turns on

[Foster48x]

Yup and then it vomits green pea soup out of the CD slot Maybe I should just perform a exorcism on the entire car. Is there a priests in the house? Pope where you at?

[SLOSpider]

You could try to run a test light on the hot wire to it then drive it and check to see if the light is going off and on too. Maybe its too many G forces for the radio to handle. I suspect a bad connection at one of your hot leads.

[SLOSpider]

And a little tip, When I rewired my radio that was last installed by some Monkey I used the key buzzer hot wire to the ignition as a key on lead to the stereo. This way even though you turn your car off the radio still plays until you take the key out of the ignition. Also you just have to slip the key in to play the radio too!

[Foster48x]

And a little tip, When I rewired my radio that was last installed by some Monkey I used the key buzzer hot wire to the ignition as a key on lead to the stereo. This way even though you turn your car off the radio still plays until you take the key out of the ignition. Also you just have to slip the key in to play the radio too!

SLO thanks for the tip. I took your advise and hooked the hot lead up to the buzzer wire so now the radio comes on when you put the key in the ignition. Pretty neat.

I'm still having the same problems as before though. The radio works fine without the car running and most of the time when the car is at a low idle. When you rev the engine the radio turns off. When you step on the brake (i think its when the engine returns to idle) it turns back on. I tested the hot wire from the radio and the constant and they both show a good 12v. I ran a new ground to the star terminal under the dash and used new connectors. The one thing I did notice and I'm not sure if it's normal or not but I got a high voltage reading on the voltmeter when I tested the hot wire while reving the engine. It went up to 18v. Is that normal?

The head unit is not blowing fuses. I think it may be going into a protection mode or something. Anybody have any ideas?

Thanks,
Rick

[ORFORD2004]

You can open the radio and check for crack connection where it is soldering

[carl55]

It does sound like it is shutting down to protect itself. It also sounds like your voltage regulator is bad.

Carl

[ITA124]

Funny thing is it only turns off if you depress the gas pedal while the car is running and will turn right back on when you hit the break pedal

Rick,

The radio turns off when you hit the accelerator (gas pedal) so you can hear that glorious engine under the bonnet (hood).

[Foster48x]

It does sound like it is shutting down to protect itself. It also sounds like your voltage regulator is bad.
Carl

Carl, I think your right about the Voltage Regulator. I tested some other circuits along with my headlights and their receiving the same voltage spike. What sucks is the Alternator is less than 6mo old. Thanks for the help with identifying the issue.

Rick

[carl55]

Glad to help. Thank you for your great posts.

Carl