Practically Classics Forum

When restoring the bodywork, the bodyshop removed the electric aerial. It had always worked well but since then it didn't anymore.
So I decided to take a look and found only one wire attached to the aerial, the other wire nowhere to be seen. I dismantled the interior panel to get at the wiring and found quite a mess : in the past an alarm had been fitted to this car and I guess whoever did this wasn't to bothered about the quality of their work.

Normally, with the ignition on, the aerial will rise when the radio is turned on and lower when the radio is turned off. Now the aerial does exactly the opposite.

With the ignition on and the radio off :
- I connect the green/red wire and then the green/blue wire : the aerial goes up.
- When I disconnect the green/blue wire before the aerial has reached its maximum height, the aerial goes down again.

- When both wires are connected, the aerial goes up. When I then disconect the green/red wire, the aerial will stop at whatever height it has reached by then.

When I turn on the radio with both wires connected the aerial goes down again.

The green/blue wire is live.

I just can't see what the problem could be and would very much appreciate any help.

Benoit

It's a Rolls Royce

There are usually 3 wires coming from the aerial, along with the actual coax, one earth, one permanent 12v feed, and one switched signal feed. The switched feed is taken from the radio itself, so when it's switched on, it will power the aerial up, once you switch it off, that feed is lost, and the aerial retracts, the constant 12v feed doing the raising and lowering.

You'll need to find which wire on the aerial is which, going from what you've said, it would appear green/red is the permanent feed. The green/blue needs tracing, or you'll need to look at the back of the radio, and see what colour the aerial feed is. If you have a modern set, it's the one that goes to the blue or blue/white wire from the radio, if it's an old set, then it could be any colour, hopefully there will be a wiring diagram on the set itself saying what colour is what.

The green/red wire is indeed the permanent feed.
Tonight I dismantled the wheelarch liner to have a look a the aerial motor : there are 2 earth straps which should connect to the front wing, but they are both missing. Could this be a cause for the problems I experience ?

ecurie wrote: Could this be a cause for the problems I experience ?

Yes I'm sure it could - at any rate I'd definately get the earth straps replaced/sorted before you worry about anything else, chances are it will leap into action when this is done. They need doing anyway, whether they ar the direct cause or not eh?

Cheers!