AM/FM radio wiring harness

[Roc]

Hello everyone,
My right cockpit speaker was out and I thought maybe the speaker has gone bad (Polyplaner).  I tested it out and it turns out the speaker is fine and I traced the problem to the wiring harness that snaps into the back of the radio.  Seems that if the harness is wiggled, it will make that speaker go out.  Nothing else is affected.  It's not that I can move it a certain way to make it happen, it knocks out that speaker as a matter of chance.  I can move the harness around and nothing can happen.  Any ideas to sure up things so it won't happen would be appreciated.

Thanks!!

[Jon Schneider]

Have you been able to determine if the problem is in the harness terminal or inside the receiver?  If the latter, you probably need to bring the receiver to an electronics repair shop (if one still exists).  If the former, you need a new terminal. 

[Roc]

Visually, both the female harness connections and the male connections on the radio look fine.  No corrosion, all posts and recepticles are even (nothing seems to be pushed in or in a way as to not plug in properly), so connections would seem to be fine on the outside.  You are right about the possibility of an internal problem, which has crossed my mind. 

[Ken Juul]

Most radio harnesses are made from several groups of wires.  Find the one that powers the intermittant speaker.  With everything connected and the radio on gently wiggle the speaker wires trying to keep the connector still.  Any change?  If yes, the connection inside the connector is probably bad.  A trip to a place that installs auto stereos can be of great help figuring out how to repair the connector, or may have a replacement connector.  If no, the only change happens when you move the connector then remove the connector and inspect the connection ports for the speaker.  A magnifying glass helps.  Some of them are the female bayonet types, some are simply wires/metal strips positioned to make contact.  If it is the female bayonet type, using a jewelers screwdriver or similar instrument try to close the gap slightly to improve contact.  If the strip type, can it be bent to give a better contact?  If the connector proves to be ok, then the radio is the next place to check.  Is it still under warranty?  If yes, send it in for repair (check first, sometimes it is cheaper to buy a new one).  If no, you have nothing to loose, open the case up and check for poor solder joints on the radio side of the connection.

[Jon Schneider]

Best way to tell if it's the harness terminal or the system connection is to switch the right and left speaker connections at the receiver.  If the problem now happens with the left speaker, then it's the receiver end; if it continues to happen with the right speaker, it's the harness, and you need a new terminal or possibly there's a short in the cabling.  You can't usually tell if the terminal is okay simply by visually inspecting it unless it's a really simple, open terminal. 

[Roc]

Thanks for the advice.  I'll look at things more closely with a magnifying glass.  The harness is a plastic rectangle made of a series of female recepticles, with matching male prongs connected to the radio.  Maybe it is a poor contact on that particular insertion.  I can give it a little bend.  I've set the balance and fade to check each of the four speakers, and it's the same one that always cuts out.  The radio is several years old, so warranty is out.

Thanks again