[Thecapitan08]

When i turn the radio on i get an ear peirceing squeal from the speakers!
I just bought a new head unit and installed it and it does the same thing! I dont understand. Someone help please its really frustrating!

[EagleAutosports]

That means there's a problem in the grounding system to the radio.

[gunz4me]

Could also be a short in the wires somewhere.

The first thing I would do is disconnect the radio ground from the factory harness ground and ground that wire directly to the vehicle's metal. Next, I would test all the speaker leads with a digital multi-meter to ensure that there are no shorts or odd resistance numbers in the speaker wires. Heck, it could even be the speakers themselves because they tend to do odd things as they start to rot out.

[Thecapitan08]

I think it may be the front amp under the radio. does it distribute power to the rear amps? b.c with the rear pluged in and the front unplugged i get no sound when i plug the front in i get the squeal!
where can i find replacement parts? i dnt want to hane to rewire the whole car. and ive been told that is required to delete the mach system! please help and thanks in advance

I have also ran power and ground straight from the battery to the radio and it still did it!

[gunz4me]

Oops, forgot about that. I figured you had bypassed the amplifiers when you installed the new head unit. IIRC there is a bypass jumper, but I can't seem to find it right now.

[Thecapitan08]

Bypass jumper?

[gunz4me]

Look at Metra Electronics Corp. part number 70-5514 on their website: Metra Electronics

ETA: They also have this one: 70-5602

[Thecapitan08]

So this would make my rear amps still work, just bypassing the front? Do you know if i would still get highs?