Hissing when I press the window button! - PeachParts Mercedes-Benz Forum

BJL-600SEL · #1 01-18-2004, 09:08 PM

I recently had a new amp, speakers and cd changer installed in my W140. When I press the center console button to roll the front driver window up, the stereo hisses and continues to do so, until I press the window button to roll the window down. Up creates static, but down clears it.

The shop that did the work (Hurley's in NoVa - the worst ever!) cannot figure it out. I assume the window switch wiring is somehow interfering with the stereo wiring.

Anyone else have this problem???

BJL

MeeM · #2 01-19-2004, 12:44 AM

The problem is most probably due to the way your new sound system was wired. One good way to wire up an amp (assuming it is mounted in the trunk) is to the run the amp's power cables along one side of the car, and run the amp's audio signal cables along the other side of the car. Experts strongly encourage this because if power cables run next to signal cables, the power cables will cause interference in the signal cables.

If the shop has done it the right way (ie put power cables on one side and signal cables on the other side) then the problem is most probably the wiring for the power windows. The amp's signal wiring may be running too close to the motor's wiring, and since there's power running in the motor cables, it will cause interference if its too close.

If you cannot move your wires anywhere else, arrange the motor's wires and the signal wires so that they run perpendicular to each other. Experts say that by arranging them this way, it doesn't totally eliminate all the noise, but it does minimize it to a level close to inaudibility.

Hope this helps. Sorry for blabbing on and on!

guydewdney · #3 01-19-2004, 07:27 AM

'cept the battery is in the trunk / boot of a w140...

there is a HELL of a lot of wires in the sills of a 140 - as i found out when i installed my amps..

first things first - run a cheap phono cable from the headunit to the amp - ouside the car as much as possible - does it still happen? fi so -then its speaker cable or headunit related. if not - get better phono (RCA in the usa...) cables / re- route them.