KIBOURED Posted March 5, 2017 Share Posted March 5, 2017 Hi, I have a 94 80 Cab with a non working aerial. I have taken the aerial out and want to bench test it but I can only find 2 wires which go to the motor, a live and earth. As far as I know electric aerials require a trigger wire but I cannot see any other connections. Can anyone tell me how to test this unit. Am I missing some other wires and/or what triggers the motor. I don't get it. Many thanks in advance. Motor model number is 8G0 035 509A Rich Quote Link to comment Share on other sites More sharing options...
Magnet Posted March 5, 2017 Share Posted March 5, 2017 Hello Rich, I feel I'm not going to answer your question very well, but I would have thought that if the aerial just has two wires coming out of it , without any signs of being modified, then it's possible that only two wires there were originally. Is it possible that the feed wire only receives power (via the radio) when the radio is switched on? It may be worth messaging Mark from Cardiff, who joined here a few weeks ago, since he has a nice Cabriolet. He is pretty handy to say the least ( don't tell him I said!) Nice chap and helpful. Good luck with it. Kind regards, Gareth. 1 Quote Link to comment Share on other sites More sharing options...
Trevor Posted March 6, 2017 Share Posted March 6, 2017 Hi Richard Chances are (not entirely sure without looking at a circuit diagram) but the aerial will probably be operated via a relay, hence the trigger wire (usually blue in colour from the stereo). Once the relay is triggered then the aerial will operate with a negative one side and a positive the other, which will then reverse when it is retracted. In this case, if you put power to it directly (+ & -) then reverse it once it has elevated then it should retract. If not, then look for a relay as this may be faulty Let us know how you get on with it Cheers Trevor Quote Link to comment Share on other sites More sharing options...
KIBOURED Posted March 6, 2017 Author Share Posted March 6, 2017 Thanks Gareth, appreciate you taking the time to reply. You could well be right but with the aerial removed I have wired it directly to a spare battery and nothing happens. Of course it could mean the motor is burnt out and your assumptions are correct. I suppose I want to find out what I should expect with the aerial wired direct to a battery this way. Most aftermarket aerials I have seen have 3 wires, live, earth and a blue trigger wire which is connected to the head unit. In my case I can't see any other wires coming to the aerial so I am confused. Will try to get a message to Mark, Thanks again. Rich Quote Link to comment Share on other sites More sharing options...
KIBOURED Posted March 6, 2017 Author Share Posted March 6, 2017 Thanks Trevor, that makes sense. A bit of history. I only recently purchased this car after tracking it for 5 years. It belonged to an elderly gent who seldom used it (he purchased it new) as they had a home in Spain and were away 6 months at a time. Any case, he called me over Christmas and said he was going to sell so I went up with my wife to collect. At the time he said the aerial had gone mad so he cut the feed wires (why he didn't just pull off the connector heaven knows). Sure enough, when I got in the boot I could see the cut cable so I re-soldered it hoping to see some action. Since then I have been searching for any other wires but everything else appears complete. I shall do a bit more research as to the relay but in my mind I would have thought the aerial would have worked if connected directly to a constant supply. Although I am a capable mechanic, wiring is a whole different ball game so input from people like yourself and Gareth is greatly received. :-) Quote Link to comment Share on other sites More sharing options...
Trevor Posted March 6, 2017 Share Posted March 6, 2017 Ah, if the aerial has gone crazy then chances are it could be something like water ingress which would explain the aerial motor being seized and also with what could be a short circuit affecting the operation. Let us know what you find, always interesting to know the outcome Cheers Trevor Quote Link to comment Share on other sites More sharing options...
KIBOURED Posted March 6, 2017 Author Share Posted March 6, 2017 Trevor, the plot thickens. I decided to strip the aerial assembly. The telescopic aerial was very tight but with some WD it's now moving. I have attached an image of the motor (which is turning freely by hand) and the circuit board and the antenna support housing. From the support housing is a wire which plugs into the circuit board alongside the positive/negative power in. I am guessing as the aerial goes up and down it triggers a pulse which tells the motor to start. You mentioned relays before, if you look carefully there are 2 x relays on the main board so I suspect it's all contained in here. Now the big question is, if the telescopic support housing isn't working right, ie not giving a pulse or something (I can't get into it to see what's going on) then do you think if I snipped this wire and used it as the trigger it might work. I know I am asking a lot but 2 minds are better than one. Rich Quote Link to comment Share on other sites More sharing options...
Trevor Posted March 6, 2017 Share Posted March 6, 2017 I would say that your suggestion would work as long as you can attach it to the signal wire from the stereo head unit then it should work. It would be worth checking the relay switches over (up / down) by powering up the system while you have it apart Quote Link to comment Share on other sites More sharing options...
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