Ok guys hoping someone has some ideas here as I'm loosing my mind. I just picked up a '96 Land Rover Discovery I. It came with a Aftermarket headunit but had a constant buzzing so I got to work.

1. Here is what I've learnt so far.
2. The buzz is constant and doesn't vary with engine speed or volume. Always the same.
3. The buzz isn't there on ACC. I can listen to music and everything sounds great. The second I goto IGN (without starting) the buzz comes. Likewise if I start the engine, buzz comes.
4. Install was actually pretty clean. Used the correct harness and didn't hack any factory wiring. I've checked all the factory wiring from the speaker amp to the sub amp and I see no slices or hacking. Just harness straight into new headunit with factory everything else.
5. Initially grounded through the harness. I re-grounded to a an unpainted chassis bolt I put in. No different.

It is driving me bloody nuts. It has to be something that is turning on with IGN that doesn't with ACC but I have no idea what.

Ideas?

 

Ground or bad ignition wires.

 

I've already tried re-grounding. Made no difference.

Truck fires up like a champ (better than my newer vehicles) and doesn't pop or crackle through the speakers. Still possible it's ignition wires?

 

UPDATE:

I wanted to see if this had anything to do with the Headunit itself. So i took a 12V ACC line and tied it too the factory remote wire (the one that controls the relay for the factory amps)

So the headunit wasn't plugged in and wasn't even in the car.

Same situation. So the problem is obviously something factory. I saw a thread about a capacitor on the back of the alternator but mine doesn't have that. Must be a different model.

 

Your transfer case is not all the way in gear.
Shift the transmission into neutral, then move the t-case shifter to neutral, and then back into hi (back and to the right)
The buzz should stop.

 

Unfortunately that didn't help..

I've given up.. Ripping all the factory crap out and just going with an aftermarket AMP/Speaker setup before I loose all my hair.

Appreciate the efforts anyways.