Power antenna wire hookup '78
 

So I'm on my 2nd brand new power antenna (different brand this time), and still can't make one go up while hooked to the car. My car has 3 wires: White (no idea what its for - no voltage ever. Ground?), Yellow (constant 12V) and Brown (signal, 12V when radio turned on). The new antenna has a red, green and ground. Instructions say red is 12V constant, and green is signal. Test light says I have power at the yellow 12v constant when key is on, and the light shows power to the signal wire when the radio is turned on. Hook it all up, ground the antenna.... NOTHING. Is the mystery white wire required for something? Help!

My wiring diags show white from radio to signal its on, terminal 'S', red is always +12V, terminal '+' , brown is ground, terminal '1'. These are whats on shown on diagrams for first set in the book, no year mentioned, just 'Type 928 USA'. Red comes from V5 on central board; white from V6 which came from J7 from the radio HU. The brown is just ground, but for some reason its done through the left rear turn indicator. The sound signal to the HU is a normal radio coax lead. The 79 MY is identical, as are 80,81,82,83. Is your radio a stock unit, and is it connected to the central board properly? Has the wiring to the antenna been hacked? Is it a powered up/down unit? Your brown may be a faded red?
My radio had no AM and one FM station when I got it, but found this was duw to the fine wire inside the coax being broken inside . Replaced it with two aerial extensions in series, worked fine. Had to replace the mast due to the nylon core breaking - they can be bought separately.
jp 83 Euro S AT 57k

I found a work around. I continually tested the yellow and brown leads with radio on and off, and when the radio was turned on, the yellow wire went dead. The brown wire went hot. Radio off, the yellow wire was always hot, even with ignition off. To make the antenna go up, they both need power. It seems as though the original antenna got power for up and down from 2 different wires? Anyway, I ran a fused 12V wire from the battery box to the red wire on the antenna (carefully routed in a heavy sheath and zip tied) with the brown wire to green and it goes up and down now!

Think about it. The aerial ALWAYS needs +12v and ground to be able to retract when you turn the radio off. Radio on , its +12V is only a signal to go up, not power for that - if you checked the current from the radio I bet it would be small. There will be contacts inside the aerial that swap the polarity over each time the aerial is up or down.
jp 83 Euro S AT 57k

posted in error