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65 Coupe Radio/CD Player turns off when blinkers are on

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1965 Coupe 289v AT Alternator Pioneer DEH-P3100UB installed in the glove box.

Problem is the radio shuts off when the blinkers are on. When the blinkers cancel the radio comes back on.

The radio is powered by connecting it to the wire that was hanging from the accessories circuit on the fuse box. I have it plugged into one of the three bullet connectors it has.

The blinkers are wired as original except the flasher was replaced last fall. The stereo is new to me and was installed by a fellow I ran into. He knew what he was doing and has installed a few for some friends also with out any problems. Radio works great except when I have to turn on my turn signals.

This may have been a problem for as long as I have had the car. On occasion the radio would shut off or some dash lights would go out. I would kick up in the area of the fuse box and they would come back on. I never associated the radio turning off with the blinkers before. I finally got under there and resoldered a connector on the back of it of the fuse box. Since then haven't had the random shut offs or when the mustang falls into one of the craters (potholes) that pepper our fine streets up here.

When I hook up a multi meter and check the voltage on all the circuits in the fuse box w/ the key on but the engine not running. When the blinkers are on it drops from close to 12v down to 10v, 12... 10...12...10 until the blinkers cancel. It does that on all the fuses except the lighter.

Would an incorrect flasher unit create this problem? I took the old one in and told them I needed a new one. Maybe I was given the wrong one.

Any suggestions?
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The wiring on the mustangs is minimal at best, you need to run wires directly to the battery for your sound system, then for your ignition sense, 10v is too low with the blinkers on, I would suspect either some corroded connections or a bad ignition switch, this reading you gave must have been with the engine not running, if it was running you should have had at least 13.2v any lower than that and the regulator needs service or replaced. There is a link at the top of the forums on vacuum and electrical diagrams, it will give the colors of the wires and what they connect to, use your voltmeter, and check out some of the wiring, don't forget the grounds, like on the rear of the cyl head on the pass side, adding an extra ground from the block to the body might not be a bad idea for your stereo. And if you cannot solve the problem, you could add a relay to you ignition sense lead that turns on with the ignition sense lead, but one of the contacts gets power directly from the battery, and don't forget fuses. Good Luck.
Thanks Rex

It was tested with the engine not running. I appreciate your help. I will be getting in there and working on it this weekend. Connecting the radio up directly to the battery should create much of a drain when the car is off should it? I realize I will need to turn the cd player/radio when getting out of the car but when reading about the cd player installation instructions. It has a wire that should be connected to a constant connection. Which currently it is not. I can go month in the winter sometimes longer depending on the weather without starting it.

So I do have a problem somewhere then right? It doesn't seem right that the turn signals should do that to all the circuits except the lighter circuit.

Shold the voltage drop that much when they blink?

Sorry I do not know anything about amps or amp draw which might be the correct way to test or ask about it.

Guy
All the stuff said is relevant. I'd also like to add that I've seen weird stuff happen from bad grounds, might be at one of the lights, and then that would make a back-feed ground suck power from the system. Sounds weird, but don't rule anything out until it has been verified.
All the stuff said is relevant. I'd also like to add that I've seen weird stuff happen from bad grounds, might be at one of the lights, and then that would make a back-feed ground suck power from the system. Sounds weird, but don't rule anything out until it has been verified.
Often overlooked is the short ground wire from engine to firewall. make sure the connections on it are nice and clean. I just dropped the resistance on my sons from 4 ohms neg batt to fender to .3 ohms simply by cleaning this connection.
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