Yesterday I installed 6.5" Alpine Type S (SPS-170A) speakers in the front doors. Everything worked fine, rest of the sound system is stock (Bose).

Today, I installed a Pioneer DEH-P4700MP head unit with a Scosche harness from Crutchfield. Tested it, worked good. Started the car, and I get a loud hum from the driver side door speaker.

I took everything apart again, re-grounded the head unit. No luck.

Switched the L+R speaker wires at the head unit, driver side speaker still hummed. Keep in mind, it only hums LOUD when the car is running, otherwise it's extremely faint.

Took the door panel off, took the speaker out, everything looked fine, but I soldered the ground connection just in case. Twisted the front speaker wires @ the head unit back together to test, and it worked fine. Started the car, no humming whatsoever.

I put everything back together, connected the speaker wires @ the head unit with wire connectors, and guess what? IT HUMS AGAIN!!!!!!!!

The guys @ Crutchfield have NO idea what it could be, and I'm extremely angry/frustrated, and losing hope.

If anyone could help me I would appreciate it....

*Edit - I think I can also hear the humming coming from the stock subwoofer in the rear as well.

 

You might need the interface that allows you to use an aftermarket HU with a Bose system. If you rewired the new speakers, bypassing the Bose wiring, you might have a bad HU.

 

I would look around to make sure its not touching the door somehow when its in there...

We had a problem on a Cavalier a few years back (my friends), we used to do custom sound systems, and we had replaced the front door speakers with 2 inch bigger ones.

So one night the whole system just started going crazy, we tried everything, finally ripped the whole system out, it turned out to be that someone had just kicked the door panel where the speaker was and it hit a bracket or such in the door shorting it out.

 

Sounds like a ground problem or a HU problem. Bu, dont rule out the fact that plug wires can affect sound. On vehicles with a massive ignition system cant use a radio cause of the affects that are given off the wires. Just fyi in case youre running a magneto or something that may be overkill...