All Speakers Just Cut Out

1993 Jeep Cherokee Sport

I recently replaced the aftermarket head unit that came with my car for a stock one out of another '93 XJ.

I forgot to connect the ground cable when installing, so this is probably my fault.

Everything was working fine (two front door speakers and two rear hatch speakers) until yesterday morning. I put a tape to aux cassette in the tape deck and the speakers all cut out. The head unit will now not eject the cassette. The display still works, and I can switch between AM/FM and Clock, but there is no sound in any speakers. I pulled the radio last night (discovered the disconnected ground) and checked the fuse. The fuse was visually fine. I also checked the two fuses for the radio circuit in the drivers side foot well (#2 and #15 I think?), both were fine...

Is there an amplifier stock in these cars?
I could not find anything that resembled one in the car. I did find what I believe is an ABS module under the rear bench, but that was it.

What next steps should I take? I am going to go pull another head unit at the scrap yard (Blaupunk in an '87 XJ, condition unknown.) Would a stock Grand Cherokee head unit be plug and play? they have a few of those in the scrap yard too.

I have read that the wires are a bit iffy on these XJ speaker systems, does anyone have a good source for a wiring diagram? Should I be checking for continuity?

I may also try hooking up the aftermarket head unit to see if the speakers and wiring is still ok.
Thanks in advance!

Test head unit outside the Jeep on a 12 volt power supply or 12 volt battery. The head unit might have an internal fuse or an overload diode that was blown. Or, maybe you let the magic smoke out.

Tim_MN said:

Test head unit outside the Jeep on a 12 volt power supply or 12 volt battery. The head unit might have an internal fuse or an overload diode that was blown. Or, maybe you let the magic smoke out.

Click to expand...

Sounds good, I guess I will pull the unit, test it, and go from there.

Before you pull it, does the front panel light up? Can you change stations on the display? If so, it is probably bad news. This would prove you have 12v and ground. The only thing that can cause all channels to go out would be every speakers ground to go away at the same time, the main ground going away but the previous test would have ruled that out, or if you still have lights and power, the audio power section having died. The night time illumination of the display is on a different circuit from the main power. That is why I asked if the display showed info. If it does, you have power and the unit is probably toast.