Question: Power antenna works great at first but not when restarted... (?)

[Vettewine]

Has anyone had this problem on their C5 convertible? The power antenna powers up just fine when the car is first started (radio on) and until the first time the engine is shut off when it powers down just fine. When the engine is restarted the antenna will not power up at all unless the vehicle is not started and driven for several hours then it works just fine again.

This happens every time I take it out for a cruise and stop for lunch or something else and then when I start up to continue the cruise the antenna stays down for the duration of the trip no matter how many times I stop and start the engine or turn the radio off and on again. It's very maddening as it always works just fine to start out with...
:confused

 

[dadaroo]

There are no diagnostic codes for Entertainment so that will not help. My thoughts are it is the antenna control at the rear.

Do you leave the radio on when you are stopped? If not, next time turn it off before you turn the ignition OFF and see if that changes anything.

It can only be the radio or the antenna control unit.


Mr. Sam

 

[Vettewine]

There are no diagnostic codes for Entertainment so that will not help. My thoughts are it is the antenna control at the rear.

Do you leave the radio on when you are stopped? If not, next time turn it off before you turn the ignition OFF and see if that changes anything.

It can only be the radio or the antenna control unit.


Mr. Sam

I've tried having the radio both on and off when shutting down the engine and the antenna goes down just fine in either situation but will not power up again when the engine is restarted unless it's been several hours since running. I'm thinking heat-related but where...? In the antenna area, the radio area or somewhere in-between...? It's bugging the heck out of me...

 

[Junkman2008]

This sounds exactly like a HEAT issue. The next time that the antenna works and you shut off the car, IMMEDIATELY open the trunk and PHYSICALLY touch the antenna. Let me know if it is really hot.

 

[dadaroo]

Here is the schematic in case you want to use it. The main power is ALWAYS HOT so that should not be an issue. You could see if you get the Dark Green control power (from the radio) to the antenna relay when you try to re-raise the antenna. That would tell you if it is the antenna or radio.

Or, maybe just unplug the antenna before you go for the initial raise and drive. After you stop, plug it back in and see if it will raise up. If it doesn't it is the radio.

Could it be some funky connector issue, yes but I doubt it.

Hope that makes sense.

https://www.dropbox.com/s/ddp5xkq54aijoxi/2001 Convwetible Antenna Schematic.pdf?dl=0


Mr. Sam

 

[Vettewine]

Here is the schematic in case you want to use it. The main power is ALWAYS HOT so that should not be an issue. You could see if you get the Dark Green control power (from the radio) to the antenna relay when you try to re-raise the antenna. That would tell you if it is the antenna or radio.

Or, maybe just unplug the antenna before you go for the initial raise and drive. After you stop, plug it back in and see if it will raise up. If it doesn't it is the radio.

Could it be some funky connector issue, yes but I doubt it.

Hope that makes sense.

https://www.dropbox.com/s/ddp5xkq54aijoxi/2001 Convwetible Antenna Schematic.pdf?dl=0


Mr. Sam

Thanks for the schematic... I have the complete shop manual (about 5000 pages) but thanks for making it easier to find...! ;<)

I'll try your idea of unplugging the antenna and see what happens... Thanks for that idea...

 

[dadaroo]

Remember, that if it does raise it does not mean the radio OK. Not sure of the internal design so no load on that circuit may mask the issue. Checking for voltage as I said would be the next step to verify if it is the radio or antenna if the unplugging does not identify the radio as the issue.


Mr. Sam

 

[Vettewine]

This sounds exactly like a HEAT issue. The next time that the antenna works and you shut off the car, IMMEDIATELY open the trunk and PHYSICALLY touch the antenna. Let me know if it is really hot.

Nope, not hot but thanks for the suggestion as it eliminates some of what could cause the problem...

 

[dadaroo]

Did you touch the antenna or the controller? The controller would be the one to check.


Mr. Sam

 

[Vettewine]

Did you touch the antenna or the controller? The controller would be the one to check.


Mr. Sam

The controller at the base of the antenna was cool to the touch.