I'm usually quite good with electronics but reading wiring diagrams is not a strength.

I'm trying to wire an up-down switch for the antenna. I replaced the OEM head unit with an after market and I don't have a way to listen to the local radio stations. I have/had the Harman/Kardon system btw but I don't think it matters and the antenna system works the same way in both stereo setups.

Could someone please guide me on which wires I need to link to. I see three wires coming from the assembly.

(B)Black= Ground/Earth
(NG)Brown Green= ???? no idea what "58" means in the diagram. Fuse?
(LGB)Light green black= Goes to the head unit

Am I correct in assuming that if I supply the LGB line with 12v/low amp power, the antenna will go up or should it be a smaller voltage that triggers the motor? Is the trigger for the antenna to go down the cut of the power? I'm worried that if I continuously push power or even the wrong amount of power through the LGB wire I might fry something.

Thanks for any help you can offer.

 

Sorry, I attached a XK8 diagram but its the same wiring with the exception of "58" being "51" in the XJ8.

 

According to the PinOut of Figure 16.1, the antennae gets B+ or battery voltage from IC10-5, the light green blue wire.
The 50 ( or 51) is battery voltage constant, not ignition switched.

I can only assume that the motor gets 12V on LGB and then drives the antennae up but gets to a point and remains quasi static, somehow in balance with the other 12V coming from 50/51/58 the brown green wire.
Then as soon as LGB goes to GND, it drives the antennae back down.
I find it hard to believe that the antennae motor is constantly driving against a hard stop, that would be crazy.

You can check pretty easy by measuring the voltage with antennae up. Both NG and LGB should have 12V.
Then you can achieve the same by sending 12V to the LGB. The fuse is 10A so it should be drawing some current.

If you need me to, I can go measure on mine, if your antennae no longer works.

Lincoln

 

Thanks so much for the reply. I agree, I can't imagine the motor being driven at all times while the antenna is up. It would burn itself out in under a minute. The LGB must be a trigger line to activate the motor and there must be an auto shut-off switch once it gets to the top. Removing the 12v from the LGB line should prove that. I'm going to give it a try right now and I report back.

 

Solved! As we thought the NG did have +12v power running to it and powering the LGB wires makes it go up.

To bring it up, 12V power must be supplied to NG and LGB wire

To bring it down, 12v power is applied to only the NG wire (or just remove power from the LGB wire)

Thanks again for the help. I needed a little encouragement and validation before testing.