Sorting out the speaker situation
 

Just got my 96 318ti a couple weeks ago and I'm slowly working through my ticket list of items, I'm finally tackling the audio and I'm running into a brick wall. All the sound coming out is clearly just pre-amp from the radio.

Here are the facts as I know it:

1. There was at some point an aftermarket head unit on the car, the BMW harness has been cut out and re-spliced back on.

2. Whoever re-wired the harness and stock radio back in did not wire two wires, one a thin black wire, the other a thin yellow wire.

3. Rewiring those two did not help the situation

4. I found that the speakers in the back (the 4") were gone, so I replaced those with some clarions and a bit of ghetto rigging.

Even after that sound is awful and after poking around I discover the factory amp, which is clearly not functioning at the moment.

So.. Does anyone know if A. There is a fuse for this thing (the guide in the fusebox says there is a 20amp fuse somewhere in the trunk) and B. If there is a way to diagnose whether it is working or not?

Is it possible that whoever put in the head unit fried the amp?

Anyone know where I can get a wiring diagram for this monstrosity?

Thanks,
Brian Horton

try searching for the wiring diagram, i have a copy from somewhere if you can't find it email me and I will send it. It's called electrical troubleshooting manual. thin yellow wire is probably just for memory power.. black usually ground. are these wires on the car harness or radio harness?

If the wires are spliced in, usually line level are phono plugs, so i can only guess he bypassed the amp or your amp is dead. if you unplug the amp and jump the speaker wires you can hear what your headunit sounds like without an amp and if it's louder, then no doubt your amp has issues.

fuse 9, (20 or 25 amp) for the radio amp.
fuse 44 for the radio as well (15a)