'90 C4 ZR-1, no sound from left side speakers - ZR-1 Net Registry Forums

mlipmd · 02-27-2022

I have sent my entire Bose system for repair - 4 speaker amps, the CDM (PIA to remove and reinstall, three times no less), and the head unit, trying to get the original system to work again.
All the caps have been replaced, the HU refurbished, the CDM redone (caps). All of this was tested and worked fine before returning to me. On reinstalling everything, at first it all worked fine, then after about 4 months, one day there was a snap, crackle, pop sound out of the front drivers side speaker and since then, no sound from the left side front or back. I have switched the rear speakers to test them that way and the left rear speaker works fine when connected to the right side, the right side speaker does not work plugged into the left side, meaning both speakers are good but the left side is getting no input. I just got another replacement CDM (which was redone and certified to be working as new) from the repair place and hooking it up, there is no change, no sound out of the left side speakers, front or back. It's unlikely 2 different CDMs are defective.
All the connections to the CDM are in tight, the wire connections seem intact, and I have not been under the dash doing anything to cut or disrupt wiring, and like I said, the system worked fine for a number of months 'till it didn't.
So where do I start to look for the problem? It must be somewhere in the wiring to the left side speakers but why would this happen spontaneously?

02-27-2022	#1
mlipmd Join Date: Mar 2021 Location: Crawfordville, FL Posts: 216	'90 C4 ZR-1, no sound from left side speakers I have sent my entire Bose system for repair - 4 speaker amps, the CDM (PIA to remove and reinstall, three times no less), and the head unit, trying to get the original system to work again. All the caps have been replaced, the HU refurbished, the CDM redone (caps). All of this was tested and worked fine before returning to me. On reinstalling everything, at first it all worked fine, then after about 4 months, one day there was a snap, crackle, pop sound out of the front drivers side speaker and since then, no sound from the left side front or back. I have switched the rear speakers to test them that way and the left rear speaker works fine when connected to the right side, the right side speaker does not work plugged into the left side, meaning both speakers are good but the left side is getting no input. I just got another replacement CDM (which was redone and certified to be working as new) from the repair place and hooking it up, there is no change, no sound out of the left side speakers, front or back. It's unlikely 2 different CDMs are defective. All the connections to the CDM are in tight, the wire connections seem intact, and I have not been under the dash doing anything to cut or disrupt wiring, and like I said, the system worked fine for a number of months 'till it didn't. So where do I start to look for the problem? It must be somewhere in the wiring to the left side speakers but why would this happen spontaneously?