Help, please, my Radio squeals when I brake!

[pillardsap]

I just bought a spyder a few weeks ago, and it has been in the shop for numerous issues. I thought I had a brake problem, so the shop pulled the wheels off, brakes were fine. They said it was the radio, so I pulled the radio fuse and the squealing did indeed stop. I put the fuse back in this morning and sure enough, when I brake it starts squealing loudly...very very loudly. When the radio is off it even does this. It stops only when the fuse is pulled. What in the world could this be? It is not a stock radio, I am not sure what kind of shop to take it to. The brake place said to take it to an audio place, but it only does it when I brake. Any help would greatly be appreciated.
Sheri

[TbonesVR4]

Sounds like your getting aolt of induced interference.I'm not really surebut I have had this happen when the RCA are ran next to the power wire for my amp.You should probrably check out the wiring behind the radio and see if the previous owner put some after market capasitor in or something.You could prob take it to any place that installs audio stuff(car toys,quality auto sound)not really sure what you got out there.

[Stealthee]

Considering braking is hydraulic then the only thing possible is something in your brake lights causing interferance.

[marshallh]

Can you describe the sound you're hearing, is it a single tone, consistent in frequency or does it change pitch?

On second thought, it could be completely unrelated - maybe the braking force causes something in the radio to short, or the wiring behind it?

Does it squeal if you shift into reverse and gun it?

[Dj4play]

One of 2 issues, most likely the 2nd issue. What you do is, if you have an aftermarket amp in the car, you need to run the radios ground, to the amp ground and run what is called a source ground, it sounds like the brake lights and the radio are sharing the same ground and and the voltage from both excedes the limitation of the ground. If you dont have an aftermarket radio or amp, simply add another ground from the radio harness to the chasis, that will eviviate your issues. Just remember ,,,knowing is half the battle (plagurized from GI JOE)

[pillardsap]

Thanks so much for the help, I will take it to an audio shop to test the ground. The sound really seems constant and does not change much. I was going to have the thing taken out and replaced with a stock unit, and then found out it was a very good radio in it's day. SO I may keep it if I can get this screaming fixed. Some friends of mine say it is coming from the drivers side speakers, door and dash. Thanks again. I believe it is a one piece head unit and can find no added amps or anything in the car. Oddly enough it has a sallelite radio antenna and I think the subscription must have been prepaid as I am getting stations, as much as I can tell over all the sqealing.
Sheri

[Quick92ES]

Ground noise is your issue. Your brakes lights work on a negative trigger. Add an extra ground to the radio or relocate it and it should be ok.

[mk_]

Money is on bad ground without reading thread.