: Antenna-Radio-Ignition Switch Problem

07-12-09, 07:45 PM
I have a 1991 Brougham with 44K miles. Anybody have any diagnostic suggestions regarding the following problem? Thanks.

1. When "cold," antenna will extend with ignition key in either the "start" or "accessory" position. The radio is off.

2. Sometimes when "cold," upon start-up there will also be static coming through the radio speakers when the antenna extends. (There is no broadcast signal from the radio unless it is turned on, just static accompanying the antenna extension.

3. The antenna will often extend when driving, even after it has previously retracted. Sometimes, this extenspon will be accompanied by loud static through the radio speakers, with the radio turned off.

4. Sometimes, when driving, with the radio off and antenna extended, I can get the antenna to retract by turning the radio on, and then off again. This does not consistently work.

5. Except for the extension on startup (or with key in accessory position), the antenna going up and down, and the static through the radio speakers, seem to be random events.

6. Static through radio speakers (with radio turned off) can occur at any time when car is running. This includes, stopped, coasting, high speed, low speed, smooth road, bumpy road.

07-12-09, 11:32 PM
I would say the problem is in the radio itself.. When the radio is turned on it gives a 12 volt signal to the antenna and it goes up... somehow it is getting that 12V. with the radio off..... and the noise when it happens...I would get another radio...

07-13-09, 04:02 PM
The problem could be in the wiring and not the radio, so before I threw another radio at the problem I would diagnose the problem. If you know how to remove the radio yourself, and are familiar with it's electrical connectors, then you can solve the problem easily. If you don't know how to remove it or are unfamiliar with the connectors, then I recommend you acquire a Cadillac OEM Factory Manual (http://shop.ebay.com/?_from=R40&_trksid=p3907.m38.l1313&_nkw=1991+Cadillac+Brougham+service+manual&_sacat=See-All-Categories).

According to the manual for my '89, the radio has three electrical connectors and a lead-in to the power antenna. If your radio is set up similar to mine, I would unplug the three electrical connectors, but leave the lead in to the antenna attached. When the conditions were similar to when the problem occurred, turn the ignition on and see if the antenna rises. If it does, then the problem is a short to voltage to the antenna motor. If the antenna doesn't go up, then the problem is in the radio, because you have taken the power from it and it cannot signal the antenna.