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Discussion Starter #1
I bought a 1988 Coupe Deville with the usual broken off antenna that I have managed to carefully rebuild and install. Someone had been there before me and pulled the relay, so when I tried to power it up nothing happened. So, I inspected every fuse and replaced the relay, and with the radio turned off the antenna immediately came up about a third of the way and stopped. Because the radio was off, I suspected some sort of short which might cause a battery draw down. So, I left it alone, with the key in the off position, for a few hours and sure enough the battery was drawn down. I disconnected the negative battery cable and I am now puzzled as to how to solve this problem. I suspect I am discovering the chain of events that caused the previous owner to pull the relay in the first place. Any help would be greatly appreciated!
 

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Master of the Dark Art of Diagnostics
2003 DHS - two-2002 DHS, 2003 SLS, 1995 Sedan DeVille, 1989 Coupe DeVille
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19,658 Posts
I bought a 1988 Coupe Deville with the usual broken off antenna that I have managed to carefully rebuild and install. Someone had been there before me and pulled the relay, so when I tried to power it up nothing happened. So, I inspected every fuse and replaced the relay, and with the radio turned off the antenna immediately came up about a third of the way and stopped. Because the radio was off, I suspected some sort of short which might cause a battery draw down. So, I left it alone, with the key in the off position, for a few hours and sure enough the battery was drawn down. I disconnected the negative battery cable and I am now puzzled as to how to solve this problem. I suspect I am discovering the chain of events that caused the previous owner to pull the relay in the first place. Any help would be greatly appreciated!
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there is a limit switch built into the antenna motor assembly -
the motor automatically stopped when fully extended or fully retracted -

usually what happened when an antenna failed -
the tape that raises and lowers the antenna shaft broke -
the motor ran constantly until someone pulled the fuse or the motor burned out -

GM offered a repair kit that was really REALLY simple to use -
problem was - shortly after replacing the antenna shaft/tape -
the motor stopped working - mainly because it ran for a LONG time when the tape broke -

GM discontinued the replacement shaft -
their solution was to replace the entire antenna assembly
rather than just replacing the broken shaft/tape
 

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92 Fleetwood 2dr cpe - FWD, 96 Seville SLS, 02 Seville
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956 Posts
These "auto" antennas have limit switches, timers or work sensors built into the motor assemblies that allow it to sense if the antenna is all the way up or down. On engine shut off, it will try to retract the antenna, and keep trying until one of the above limits is reached.

If your antenna is not moving past a certain point, then it could
  • halved
  • cable has been shortened (and it is coming off the motor gear)
  • the limit switches are compromised (shorting out)
You can check the first 2 by removing the antenna mast from the motor. Unbolt the top of the antenna from the body of the car. Turn the radio on and see if the antenna is completely ejected. You might have to pull a bit to clear the gunk inside the tube. Once out, check the length and freedom to extend by extending it full length. Check that there is 12-18" of cable still visable once extended.

Install the mast by first turning on the radio (which assumes the mast is extended), then turn radio off and quickly inserting the cable into the tube while the motor is doing a retraction. You might have to rotate the cable to engage the teeth.
 

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Discussion Starter #4
=====================
there is a limit switch built into the antenna motor assembly -
the motor automatically stopped when fully extended or fully retracted -

usually what happened when an antenna failed -
the tape that raises and lowers the antenna shaft broke -
the motor ran constantly until someone pulled the fuse or the motor burned out -

GM offered a repair kit that was really REALLY simple to use -
problem was - shortly after replacing the antenna shaft/tape -
the motor stopped working - mainly because it ran for a LONG time when the tape broke -

GM discontinued the replacement shaft -
their solution was to replace the entire antenna assembly
rather than just replacing the broken shaft/tape

Thank you!
 

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Registered
Joined
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7 Posts
Discussion Starter #5
=====================
there is a limit switch built into the antenna motor assembly -
the motor automatically stopped when fully extended or fully retracted -

usually what happened when an antenna failed -
the tape that raises and lowers the antenna shaft broke -
the motor ran constantly until someone pulled the fuse or the motor burned out -

GM offered a repair kit that was really REALLY simple to use -
problem was - shortly after replacing the antenna shaft/tape -
the motor stopped working - mainly because it ran for a LONG time when the tape broke -

GM discontinued the replacement shaft -
their solution was to replace the entire antenna assembly
rather than just replacing the broken shaft/tape
Thank you!
 

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Registered
Joined
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7 Posts
Discussion Starter #6
Hi
I have a 1988 Cadillac Coupe Deville that has a power antenna issue. I have replaced the relay, the entire antenna with a rebuilt one, and was meticulous about the installation. A bit of background may help! This has been a process of elimination since I purchased the car last year. When I took the inner wheel well apart to diagnose the problem, the antenna’s spool was missing, so I had no choice but to acquire an entire unit, which I rebuilt. Once installed, with a new relay, which had also been missing, the unit went up about half way and stopped. I recently purchased a rebuilt unit and just installed it to no avail. I know there was power to the unit when I installed the previous one, but during this installation I took my circuit tester and there was no current at the wires. This probably happened during the first antenna failure, which burned up the unit’s internal contact points. I figured it was a fuse and continued with the install. When done, I looked for the fuse on the under-dash panel, which the manual clearly shows as #13, but this fuse panel is different and does not have a specific antenna fuse. I have consulted my shop manual, which is not covering this particular aspect. So, at this time I am at a loss as to which way to proceed. Any help would be appreciated!

All the best to you!
Michael Duty
 

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Discussion Starter #7
=====================
there is a limit switch built into the antenna motor assembly -
the motor automatically stopped when fully extended or fully retracted -

usually what happened when an antenna failed -
the tape that raises and lowers the antenna shaft broke -
the motor ran constantly until someone pulled the fuse or the motor burned out -

GM offered a repair kit that was really REALLY simple to use -
problem was - shortly after replacing the antenna shaft/tape -
the motor stopped working - mainly because it ran for a LONG time when the tape broke -

GM discontinued the replacement shaft -
their solution was to replace the entire antenna assembly
rather than just replacing the broken shaft/tape
Thank you!
 

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Registered
Joined
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7 Posts
Discussion Starter #8
These "auto" antennas have limit switches, timers or work sensors built into the motor assemblies that allow it to sense if the antenna is all the way up or down. On engine shut off, it will try to retract the antenna, and keep trying until one of the above limits is reached.

If your antenna is not moving past a certain point, then it could
  • halved
  • cable has been shortened (and it is coming off the motor gear)
  • the limit switches are compromised (shorting out)
You can check the first 2 by removing the antenna mast from the motor. Unbolt the top of the antenna from the body of the car. Turn the radio on and see if the antenna is completely ejected. You might have to pull a bit to clear the gunk inside the tube. Once out, check the length and freedom to extend by extending it full length. Check that there is 12-18" of cable still visable once extended.

Install the mast by first turning on the radio (which assumes the mast is extended), then turn radio off and quickly inserting the cable into the tube while the motor is doing a retraction. You might have to rotate the cable to engage the teeth.
Thank you!
 
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