(Also posted in ZR-1 section so forgive me for having 2 of these).
Has anyone on here replaced their antenna cable from the CDM to the left rear quarter of the car?
I have a problem with poor radio reception and fuzzy sound and think it's related to the plug that goes into the CDM which had been bent at a 45-60 degree angle and possibly broke the small diameter copper center wire in the cable. There is nothing wrong with either my CDM or HU as they have both been refurbished and CD's and cassettes play and sound great, so I think the problem is the antenna cable itself, and the logical area is that the plug has been damaged.
To confirm this, I could plug in another, aftermarket, antenna and see how it works, but If the antenna or cable is the problem I still need to know the path of the cable to either replace it or correctly splice in a new end leading to the CDM.
I assume it goes left to right from the CDM behind the center of the dash, behind the driver side knee panel, along the left door sill underneath the carpet, but I would like to know for sure before digging for it., as well as any tips for doing this.
Searching on here and Google and YouTube offers nothing, only you guys have the answers.
Thanks.

 

Doesn't go to the 'left quarter'! I believe the mating connector in the harness is closer to mid-rear body panel. > obviously wrong!!

I would think it's routed back the right side with the rear harness. > this is correct BUT it crosses the car at the rear compartment partition

I asked the 'seller' of the proper antenna to post additional snapshots of his 'for sale' just to help you. Sent you a link via PM to his offering to be sure you saw it. Maybe just do a correct male connector to the coaxial @ the CDM.

8A-203-0 in the FSM.

Once Is Generally Enough!!

 

I would like to put on a new male connector to the cable at the CDM but there doesn't seem like much slack in there to work with the cable. I can loosen the CDM to gain access to the cable input on the CDM but if I can avoid it, I do not want to go through the gigantic PIA hassle to take it out again and put it back. I've already done it twice replacing the CDM twice. I'd rather just try and loosen it and put in a new cable end then connect that to my existing antenna cable, or replace the entire cable.
When I found the connection between my cable coming from the antenna, and the cable coming from the CDM, the connection is located underneath the left side of the rear fender. You have to remove the plastic molding under there and it is lying in there enclosed in some foam rubber, probably as a noise suppression arrangement. The antenna cable comes straight forward through the grommet in the rear while the cable from the CDM seems to go straight forward under the left body panel and disappears forward of the pivot for the rear hatch strut under the carpet. If it comes from the right-sided harness how does it get over to the left side?
If the cable from the CDM is on the right side in that harness, I should be able to find it underneath the carpet along the door sill, and if so, then I could cleanly splice on a new cable with a new male plug to go in to the CDM.
To test if the problem lies with my CDM cable (plug) I should first buy a cheapo antenna and connect it up to the CDM and see if that solves my reception problem.
And BTW, I didn't get your PM yet, but thanks.

 

I saw that page, 8A-203-0 in the FSM, but I don't think or know if the CDM cable is included in that electrical harness. That might only be for electrical wiring to the rear brake, signals, backup lights, and the antenna relay, not containing the cable too. There is no antenna cable crossing underneath the rear deck, as there is for the wires leading to the antenna relay located to the left of the rear hatch lock. That cable from the CDM is under the left fender going forward like I said.
That pic of the antenna shows the female connector on the antenna lead that I knew of (because I already accessed it underneath the left rear body panel), but no indication of the course of the cable from the CDM.
So I have to keep searching, but I don't know where else to look besides taking the car apart unless someone else who has done this chimes in.

 

Inspect the left and right storage compartments and I'd think you'll find it routed towards the rear at either the left or right 'lock pillar' - I'd think it visible or 'by feel' without much effort. You're thinking 'left' so concentrate there first. If you can put you hands on the 'pass through' on the right side I'd think you could 'feel' the coaxial. I'd think if it's on the left side there would be no reason to go across the dash but maybe cross the car under the rear storage.

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The following added something around 6:15 PM

This image isn't in a '90 FSM but a '91 that has the same CDM location as a '90 has this in the body wiring section. '90 the same?

 

Well I'm getting closer.
It's not in/under the storage compartments.
I took off the plastic trim to the rear of the driver's side door (the "lock pillar" ?) and if you pull back the carpet and foam and look in there, you can see the antenna cable coming from the left rear under the quarter panel. It then courses to the right under the carpet behind the seat and disappears from view and beyond reach or feel through the carpet.
I took off the panel behind the passenger side door and the door sill panel, and peeled back the rug and foam, and there is no cable visible in there or coming over from the left side that I can see as of now.
Under the carpet on the floor, at the corner of the sill extending the length of the door, there is an inch wide rectangular black plastic sleeve or trough with a taped up heavy bunch of wires in there, but again if you trace that forward to under the PS dash panel, in front of the speaker, you can see a taped up large number off wires going into that, but no antenna cable.
So I don't know yet the complete path of the antenna cable. Could the cable pass underneath the carpet on the passenger side of the transmission hump? Or could it go forward underneath the center console tray and ashtray area to get to below the PS dash pad and onto the CDM?
Tomorrow I'll look at the center console area and pull off the PS knee panel again and get a better look in there to try and find it.
And BTW, I have no AM radio reception, so I am 99.9% sure this is an antenna problem.

 

This in the '89 FSM (same antenna) is routing 'in the quarter'. You can see it up the lock pillar like the '90 also.

 

Too bad there's no continuation of that pic on the left hand side, like turning the page in a book of maps.
I'll try and find the rest of the course of the cable tomorrow.

 

More on the antenna course through the car.
Again after taking down the PS knee panel and with lights and a mirror, I found the cable coming up from underneath the carpet going to the right, at the base of the dash, and then disappearing again. It apparently goes over the top of the CDM box to come down on the right side and insert into the plug at the right forward corner of the CDM. And of course, this is totally out of sight unless you lie down and use a mirror, and totally out of reach unless you take down the CDM box. I believe the cable lies underneath the carpet alongside the transmission hump where it joins the floor and then comes out the top of the carpet as it goes right, into the area behind the PS dash over to the CDM.
I did not take apart the center console looking for it, I believe it just goes under the carpet.
Turns out the end of my cable was not fully inserted into the CDM socket. I was able to remove it and pull it out from the left side and see that the male tip of the plug was loose, could be rocked back and forth in the plug, but seemed firmly attached, so the center wire seemed intact. Using pliers I was able to push this pin (?) back into the plug where it seated firmly, was not shorting out, and decided to reinsert it into the CDM socket and see how it worked.
Thankfully, my SO has smaller hands than I do with a very strong grip, and again using lights and a mirror, she was able to get that plug back into the socket, and firmly seated too.
Now for the moment of truth - I turned on the radio and the reception, although not perfect is WAY better than before, some fuzziness, not much static, but good enough to tolerate. And, since I am at least 40 miles away from the nearest radio station, that may be as good as it gets down here. I'll have to ride around and see how it is. My other cars cars have perfect reception and no static or fuzzies.
And I'll have to see if I have any AM - forgot to check that but I never listen to that anyway.