Hello All.
As many of you know who regularly visit this site, i have a `94 440 2.0i. After many months of hard work, i have just been able to buy a really nice system for her. It comprises of a Kenwood CD head unit, front and rear Pioneer Accelerate speakers, 2xRockford Fosgate Punch Competition 12" Subs and 2xJBL GTO 4000 Amps to run it all. Its all been in the car and running really well-until the other day. I had to take the dash out for a few routine bulb changes and i dropped a bulb down the back (of the dash where the heater controls are)-so, i disconnected the head unit, un-done the screws, took it out and retrieved the bulb. I put it all back together and thought nothing of it. Until i started the engine. For some now unknown reason, i now have interferance through the whole system. It makes a funny buzzing noise through the front and rear speakers (not subs though) when turning the ignition, then a very annoying high pitch noise when the engine is running. When the head light switch is set to "0", there also seems to be a similar buzzing noise to leaving the door open with the lights on, but when you turn the lights on fully, it stops. This interferance can also be heard very faintly through the subs when the component speakers are disconnected. But that is not all. When the seatbelt indicator "clicks", the brake pedal pressed and even the interior fan turned on, you can hear different levels of noise/feedback through the speakers. However, when the ignition is turned off completely and the keys removed, there is no interferance at all and it sounds fine. I have been over the car a dozen times and checked all my Earth/Ground wires and checked for loose connections/faulty wires and can find none. And before anyone suggests it-the RCA and speaker cables are on the opposite side to the 4 gague power cable. As i said, the stereo was working fine so i dont think its the wiring. My Dad has said i may need a Surpressor or somthing like that on my headunit to filter out the noise. Could this be what im looking for or am i way off?? Any help or similar experiences (preferably solved ones) will be greatly appreciated. Dont hold back with replies, send anything-i may not have tried it yet!!!!!!!

Many thanks in advance, Depressed Dan.