Resto Sound Help needed. Electrical? Amp? (4 Viewers)

[FFFbuff]

I’m at the finish line restoring a 1996 and hoping someone can help with an electrical issue.

When we plug the factory amp in, we blow a fuse and lose power to the aftermarket head unit, clock, and dome lights.

When we unplug the amp everything works, but no sound whatsoever.

Everything worked before we started the project, but it’s taken over a year with the body shop and the battery died too many times to count while being worked on before being replaced towards the end of the project.

In the resto, everything came out- dash, door cards, headliner, all panels. Speakers were replaced with the same OEM size used by lots of users on this forum.

Any help is appreciated. Thanks.

 

[voodu3]

I’m pretty sure you have to bypass the factory amp with an aftermarket head unit. I know I took mine out when I replaced the radio and speakers.

 

[FFFbuff]

I’m pretty sure you have to bypass the factory amp with an aftermarket head unit. I know I took mine out when I replaced the radio and speakers.

Thanks. The aftermarket head-unit was working with the OEM amp before we started the project. Not sure if one of the changes above would change that, but definitely under consideration.

Or maybe it was hooked up differently before the work was done? Not sure how that would work.

 

[voodu3]

There are a bunch of threads on here that discuss bypassing the factory amp. I assume that the original head unit doesn’t send power to the speakers like an aftermarket one does.

Google Search

 

[FFFbuff]

There are a bunch of threads on here that discuss bypassing the factory amp. I assume that the original head unit doesn’t send power to the speakers like an aftermarket one does.

Google Search

Thanks. I think this may be the issue, but wanted to see if someone else had similar symptoms.

Not sure why it would work before all the work and then stop working after the work with the same components.

 

[Malleus]

The OEM amp will power the speakers with an aftermarket head unit. I have two running this way now.

It would help if we have (any) information on what your system looks like.

 

[FFFbuff]

This as the response back after reading those threads-

Potentially. But it still doesn't explain the fuse blowing when I didn't even have the stereo or clock in the car. I know for sure there is an unused connector back there. The stereo harness is wired in nicely to the factory harness and only plugs into the stereo one way.

 

[FFFbuff]

The OEM amp will power the speakers with an aftermarket head unit. I have two running this way now.

It would help if we have (any) information on what your system looks like.

 

[FFFbuff]

Thanks for the help.

 

[Malleus]

@jonheld wil correct me if I'm wrong, but I believe there are two stereo connectors because one OEM option used used the amp and one did not.

I was kind of hoping for details on your head unit..."wired nicely into the harness" doesn't help me too much.

If I understand your comments (and I'm not sure I do), you're saying the amp is blowing the fuse? Sounds like a ground problem.

 

[FFFbuff]

Thanks again. The headunit was in the LC when I bought it and was working fine for the two months before it went into the shop. It’s just a single din Jensen unit that was next up to be replaced. Was hoping to get it all sorted and working before dropping it off at the audio shop or at least be able to give them some direction so they don’t have to dig into a newly put together LC.

 

[Malleus]

If your amp is causing a fuse to blow, it's drawing more current than is allowed on that circuit...the only way (that I know of) that this can happen, if the amp isn't connected to the stereo, is if one of the outputs is shorted to ground. I'd recommend pulling out the EWD and physically checking each wire in the amp circuit (not just its sub-harness) for frayed insulation.

You should be able to simulate the problem by jumping the power and ground terminals in the body harness side connector. If that doesn't cause the fuse to blow immediately, there might be a short in the amp, on its board. Open the case and inspect the board for a leaking/leaked capacitor or a shorted trace...it should be obvious.

FWIW, I've never seen, or heard of, any audio shop that can troubleshoot their own work, much less anyone else's.

 

[reklund5]

Get into the EWD and check for short to ground on the power circuit to the amp. Also check for short to power on the ground circuit to the amp. Good chance a wire got pinched during install, or perhaps one of those crimp-cap connectors on the radio adapter harness came apart and got reassembled incorrectly.

 

[FFFbuff]

If your amp is causing a fuse to blow, it's drawing more current than is allowed on that circuit...the only way (that I know of) that this can happen, if the amp isn't connected to the stereo, is if one of the outputs is shorted to ground. I'd recommend pulling out the EWD and physically checking each wire in the amp circuit (not just its sub-harness) for frayed insulation.

You should be able to simulate the problem by jumping the power and ground terminals in the body harness side connector. If that doesn't cause the fuse to blow immediately, there might be a short in the amp, on its board. Open the case and inspect the board for a leaking/leaked capacitor or a shorted trace...it should be obvious.

FWIW, I've never seen, or heard of, any audio shop that can troubleshoot their own work, much less anyone else's.

Thank you. Passing this along now. Really appreciate the help.

 

[FFFbuff]

If your amp is causing a fuse to blow, it's drawing more current than is allowed on that circuit...the only way (that I know of) that this can happen, if the amp isn't connected to the stereo, is if one of the outputs is shorted to ground. I'd recommend pulling out the EWD and physically checking each wire in the amp circuit (not just its sub-harness) for frayed insulation.

You should be able to simulate the problem by jumping the power and ground terminals in the body harness side connector. If that doesn't cause the fuse to blow immediately, there might be a short in the amp, on its board. Open the case and inspect the board for a leaking/leaked capacitor or a shorted trace...it should be obvious.

FWIW, I've never seen, or heard of, any audio shop that can troubleshoot their own work, much less anyone else's.

The fuse blows when the amp is connected to the headunit. When the amp is unplugged from the headunit, the headunit has power, but no sound. Thanks.

 

[Malleus]

The body side harness connector you're using requires the amp, so it makes sense that you get no sound when it's disconnected. It also makes sense that the fuse doesn't fail when the amp is disconnected, because the circuit's not complete.

I assume you don't have a multimeter? That'd be the quickest way to find the problem.

 

[FFFbuff]

The body side harness connector you're using requires the amp, so it makes sense that you get no sound when it's disconnected. It also makes sense that the fuse doesn't fail when the amp is disconnected, because the circuit's not complete.

I assume you don't have a multimeter? That'd be the quickest way to find the problem.

Thanks. Asking now

 

[Malleus]

OK, here's the diagram, for reference:

 

[Malleus]

Connectors S11 and S12 (marked with "A" and "B" in circles on the wiring diagram), join the amp and head unit (page 159 has the diagrams of these connector housings, so you can ID them). They share a pair of grounds, in each connector, the typical white with black tracer in "B" at terminal 11 in both connector housings and a brown wire between the "A" connector and the head unit's R1 connector.

I'd start with these two wires and make sure there is no continuity between either end and the body when the power is off. If there is, that's the short.

Since you are sure everything worked before it was unplugged, it probably still does and the problem is a grounded wire somewhere.

 

[Malleus]

The images I posted are from the 1996 EWD. If you don't have a copy, you can download one from the Resources forum.