Car won't start when constant power sent to stereo harness

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ACJJ619
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E30 Zone Newbie
Posts: 125
Joined: Fri Feb 20, 2015 11:00 pm
Location: Reading

Post Mon Aug 10, 2015 9:35 am

Yesterday I tried my hand at wiring in my stereo and after a lot of confusion, I managed to get the stereo turned on and working. However because I can't find my stereo cage, I didn't actually keep the stereo plugged in so the plug was just hanging redundant, doing nothing all night. Or so I thought...

This morning the car wouldn't start. It showed signs of life in that the dash lights flashed on and off when I turned the key, but the engine did nothing at all. It was like the battery had been drained overnight.

I then disconnected the yellow wire (12v constant) from the plug, and the car started perfectly. What's going on there? The plug wasn't plugged into anything. That wire shouldn't have been supplying power anywhere, so how could it prevent the engine starting?