Radio antenna cable

[mlipmd]

My '90 ZR-1 has had the entire Bose system rebuilt - HU, CDM, all 4 speaker amps, and has been working fine until recently when the radio reception became poor and scratchy in sound quality. Cassettes and CDs play clear and distinct, but the radio sounds like the antenna is bad or the connection is bad. I would like to temporarily hook up another antenna or clean the existing connectors but I do not want to take out the CDM again (have already done that 3 times) to reach the antenna connector in the right hand corner and I am sure that connection is clean.
I thought there was a connection from the radio cable to the antenna connection underneath the left rear quarter panel but I cannot see it after removing the black plastic trim piece below the rear window. Is there something else or more that needs to be removed to see in there, is there another connection I can get to in there, or does the antenna cable just end at the antenna itself where it is screwed into the side of the antenna?
I can't find much help in the FSM or EDSM, or for that matter, Google or YouTube, so I'm asking the experts here for assistance.

[AndrewL]

Remove the left rear external trim panel that you had removed, then remove the guide trim for the cargo shade that sits under the trim panel and dig around behind the foam insulation. You will find a connection point for the antenna lead where it simply unplugs (roughly halfway along the trim you just removed).
I did this a few weeks ago but amazingly I don't seem to have taken photos while doing it.

[richarde]

17969


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[richarde]

Just tucked in beneath the trim panels above the left rear speaker


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[mlipmd]

Thanks for that. I'll go look again. I thought it was way back under the rear deck.

[-=Jeff=-]

My '90 ZR-1 has had the entire Bose system rebuilt - HU, CDM, all 4 speaker amps, and has been working fine until recently when the radio reception became poor and scratchy in sound quality. Cassettes and CDs play clear and distinct, but the radio sounds like the antenna is bad or the connection is bad. I would like to temporarily hook up another antenna or clean the existing connectors but I do not want to take out the CDM again (have already done that 3 times) to reach the antenna connector in the right hand corner and I am sure that connection is clean.
I thought there was a connection from the radio cable to the antenna connection underneath the left rear quarter panel but I cannot see it after removing the black plastic trim piece below the rear window. Is there something else or more that needs to be removed to see in there, is there another connection I can get to in there, or does the antenna cable just end at the antenna itself where it is screwed into the side of the antenna?
I can't find much help in the FSM or EDSM, or for that matter, Google or YouTube, so I'm asking the experts here for assistance.


Dumb question.. have you replaced your exterior light with LEDs or did you do LED headlights? If so, what brand ones did you use?

[mlipmd]

No, I have replaced the underhood lights and the reverse lights with LEDs, not headlights or any others.

[mlipmd]

AndrewL and Richarde - question about the ends of the antenna leads.
Does the end of the antenna cable coming from the CDM have a male or female end?
Does the end of the cable coming from the antenna itself have a male or female end?
In pictures of both of these it seem like the cable ends are both male and that means there has to be a female-female connector between them in that location.
Is that true? Or is one of these male and the other female?
The reason I was asking is that I was thinking of inserting an antenna signal booster in there and wiring up the power to the antenna relay so that it would only be powered on when the the radio was on and the antenna was up.
Thanks.

[mlipmd]

Found it, dug it out.
FYI, the end of the antenna cable coming from the CDM has a male connector, the cable coming from the antenna has a female end.
So if I put in a signal booster I probably have to cut off and reverse the connectors to insert it in the line, unless it is not unidirectional in how it works.

[Corvette95]

Your problem probably isn't the antenna. When you R/I's your CDM for repair did you look at the male end to the CDM under the passenger dash? That connector is a weak point in the system. Also, and not really in the FSM, the harness to the CDM has "Bose drain" lines running parallel to the speaker/power harness. If any of those wires (clear looms with visible wires) are broken it will allow static into the radio reception. Very very little on this in the FSM. A signal amplifier will likely make it worse. I recommend you check those connection and possibly adding the antenna ground harness from a 93+ car (not 100% sure on the year the ground harness was added).

[mlipmd]

Thanks for that.

[mlipmd]

Corvette 95 - the center of the male end of my antenna cable as it plugs into the CDM was bent, at maybe 45-60 degrees, but the end is intact, not broken off. It's possible the the tiny center copper wire in there has been broken but there's no real good way to know that, other than poor reception and static. If the antenna lead was more accessible I would think about splicing on a new end and maybe having to add a short plug-in extension to reach the CDM box, but there's really no slack in that cable to work with. And again taking out the CDM is a royal PIA. Do you or anybody else on here know the path of the antenna cable after it leaves the CDM on its' way to the left rear quarter of the car? It may be easier and more reliable to just replace the whole cable, or at least get to it where it's easier to work on it, or where to look for it so I could splice on a new end to reach the CDM. It if was underneath the PS rocker panel/rug for example, it would be easy to do a quaility splice there and add a new length of cable up to the CDM. Another, way easier option, is to replace the antenna with an interior flat one that lays on the dash or sticks on the windshield and disconnect the plug/relay for the power antenna. Or I could just forget about having quality radio sound.

[Corvette95]

While can't image a ZR-1owner having an antenna laying on the dash... the single coax cable is one piece to the drivers rear corner. Definitely replaceable but it's a job. Post a picture of the antenna lead at the CDM. The cable can definitely be broke or damaged with the wire still basically attached. I have never had any success repairing an antenna cable but there is probably a way. The CDM removal isn't really that hard the second time you do it. You can test it with a cheap $10 antenna from the internet and see if that makes a difference (be sure you have the motor running) and check for signal sound. If it is better, then you know.

[mlipmd]

Do you have any idea of the path the antenna cable takes from the CDM to the left rear of the car? Going from right to left behind the HU in the dash, behind the DS knee panel, along the DS door sill beneath the carpet? It would be easier if it went along the right side of the car.
To post a pic of the antenna lead I have to take this whole thing apart again and if I do that I may as well replace the cable end. There is also nothing to see now that the tip is again straightened out, you can't see a possible broken copper wire inside.

[dredgeguy]

Pull the head unit out and send it to the guys in FL or Dr. Don and have an aux cable hard wired to the cassette. They will give you a 4 foot cable so you can run it into the center console and hook up a small XM radio. The XM radio antenna can mount under your rear plastic hatch trim under the latch. Everything is hidden and looks stock but you have the wonders of perfect clear radio. My XM radio would not respond to the remote control as it could not see through the center console lid, we installed an RF repeater in the vent so all I have to do is aim my remote to the vent and change channels.

[mlipmd]

And WTF yesterday my radio was pretty clear without the static and the reception was good. Changes in atmosphere? The weather has been clear so I have no clue why it works better one day and not the next. The only explanation to me is an intermittent bad connection somewhere in the antenna circuit as both the HU and CDM have been completely redone and cassettes and CDs play great.

[mlipmd]

My saga ends, for now, and found the path of the cable through the car - if anyone is interested.
From the connection under the left rear body panel, the cable comes out in front of the targa-top pillar above the door lock, goes underneath the carpet and some insulation behind the seat, then disappears from sight and feel, going down and to the right behind the driver's seat. I believe it then goes forward underneath the carpet in the angle between the transmission hump and the floor, comes out at the top of the carpet on the right side behind the PS dash as it courses to the right and goes over the CDM to where it plugs into the right front corner of the CDM box. Of course this is out of sight unless you use a light and a mirror or take the CDM box down.
Anyway, I think I have my original problem solved. The male plug was only partially plugged in to the CDM socket and the tip of the plug was loose and dangling from the plug end. It was firmly attached so the copper wire inside was then intact.
I reinserted the tip into the plug, it seated firmly, there was no short, so I decided to use it again and see if it worked. Then with the help of my SO, whose hands are way smaller than mine but with a very strong grip, again using a light and a mirror, she was able to reinsert the male plug into the CDM socket, very firmly.
And then the moment of truth, turning on the radio. It works, way better than before, not perfect but with way less static and fuzziness, acceptable to listen to. And being 40 miles away from the nearest radio station, that may be as good as it gets down here but I'll have to ride around to really see how it is.
I forgot to try the AM, but I never listen to that anyway. So I'm happy right now.

[-=Jeff=-]

you do know the cable connecting to the CDM is only about 6" into another Antenna cable the runs to the back of the car right?

So it could be as easy as replacing that short cable

[mlipmd]

The cable from the CDM goes left under the PS dash, then turns rearward underneath the carpet along the transmission hump, turns left still under the carpet behind the driver's seat, then up to the left rear quarter where it connects to the antenna cable. There is only one connection between the CDM and the antenna, as is shown in post #$3 above. That CDM cable is maybe 9 feet long.
I can't post a pic but here for example is one --
https://www.ebay.com/p/718181590