Well here goes! I just bought a 98 disco not long ago. The factory radio was locked out so I figured instead of paying for the unlock code I would put in a new kenwood So I had a hook up for my sirius. Anyway, bought the adaptor harness, and had everything hooked up by a friend that works at a local sound shop. We got everything in and there is some crazy noise coming out of the speakers. So of course we start trying different options to knock out the noise....ground loop isolators, capacitors, grounded the engine to chassis, regrounded alternator, even went as far as running new lines for power and ground directly from battery. And no luck. There is a whine when the truck is off but when it is running the noiseheadache material! Anyone ever have this problem and get it fixed. I see alot of posts on here about radio noise but no posts from anyone who has ever fixed the problem. Everyone cant be driving around with a stock stereo. Please help! I think the next step is going to be a good set of plug wires that are insulated well. and hooking a spare speaker up to the headunit before the signal goes to the amp trying to rule out the amp.

 

Had a similar problem (maybe not the same though). found it was pinched wires in the rear drivers side door. Straightened wires, checked for nicks and good to go. not always the ground. I ruled that out early on.