1972 Power Antenna

[DMX]

We have a 72 coupe and am trying to diagnose the power antenna system. I have traced the wiring from the antenna to inside the rear compartment and have found the 3 wires have been cut off. There is no trace of them moving forward. I cannot find any info in regarding wiring diagrams and location of a relay which I am sure is required.Is there a procedure to power up the antenna to see if it is operational. I am thinking the previous owner manually raised and lowered it and would that damage the antenna.
Thank for any info you can offer.
Danny

 

[Vettehead Mikey]

'72 Corvettes did not come with power antennas. They had a rigid mast.

 

[SVO]

As Mikey has pointed out, '72's didn't come with power antennas. 1978 was the first year that the U75 power antenna was offered as an option for C3's. Since your power antenna isn't probably means that either the motor went bad or the drive cable suffered a failure. The aftermarket antennas either had a manual switch for raising or lowering the mast or was wired into the radio so that the mast was raised when the radio was powered up or lowered when turned off. If you are wanting a working power antenna, you are probably going to have to look for a new aftermarket unit.

 

[DMX]

Power Antenna

As Mikey has pointed out, '72's didn't come with power antennas. 1978 was the first year that the U79 power antenna was offered as an option for C3's. Since your power antenna isn't probably means that either the motor went bad or the drive cable suffered a failure. The aftermarket antennas either had a manual switch for raising or lowering the mast or was wired into the radio so that the mast was raised when the radio was powered up or lowered when turned off. If you are wanting a working power antenna, you are probably going to have to look for a new aftermarket unit.[/QUOTE

There is no wiring for the antenna beyond the rear storage compartment so it looks like it has never been powered up. There are 3 wires leading into the antenna but I do know which wire to power up and what the other 2 may be for other than possibly a ground. I would think a relay would be required in the system. Can anybody offer some info on this.

Thanks again,
Danny

 

[bill81vette]

3 wires for the antenna,one is a ground the other 2 are for up and down.depending on if the power to the radio is on or off.
Good luck

Sent from my XT1650 using Tapatalk

 

[Antz81]

3 wires for the antenna,one is a ground the other 2 are for up and down.depending on if the power to the radio is on or off.
Good luck

Sent from my XT1650 using Tapatalk

Could be the other way around as well.

 

[mkapp7879]

Trying to determine if it's a GM antenna.......
What colors are the 3 wires?

 

[SVO]

@DMX -
There is no wiring for the antenna beyond the rear storage compartment so it looks like it has never been powered up. There are 3 wires leading into the antenna but I do know which wire to power up and what the other 2 may be for other than possibly a ground. I would think a relay would be required in the system. Can anybody offer some info on this.

Thanks again,
Danny[/QUOTE]

The '78 U75 power antenna used a relay, which the assembly manual shows to be located in two different areas, depending on if it was early or late model '78. If you want to chase this futher, a wiring diagram for a 78-82 model might be helpful. As Bill pointed out, one wire could be the ground, one wire to raise the mast, one wire to lower. The motor would be reversible, depending on how power was applied.

@mkapp 7879
A wiring diagram for your particular car will give you the wiring colors & gauge for a factory install if it was an option offered for your car. It might be better to start your own topic rather than hi-jacking one in progress.

 

[mkapp7879]

@mkapp 7879
A wiring diagram for your particular car will give you the wiring colors & gauge for a factory install if it was an option offered for your car. It might be better to start your own topic rather than hi-jacking one in progress.

Uh, did it occur to you I'm asking the poster the color of his wires so I can tell him the hookups for up and down??
If his colors are green, gray, and white that might indicate a GM unit and there are specific hookups for correct operation.
Just trying to determine if someone in the fast tried to install a GM antenna and couldn't figure it out.

 

[mkapp7879]

The '78 U75 power antenna used a relay, which the assembly manual shows to be located in two different areas, depending on if it was early or late model '78. If you want to chase this futher, a wiring diagram for a 78-82 model might be helpful. As Bill pointed out, one wire could be the ground, one wire to raise the mast, one wire to lower. The motor would be reversible, depending on how power was applied.

For a GM antenna either the gray OR green wire is the ground. Depending on the direction of operation.

Again, to original poster, what color are the wires.

 

[mkapp7879]

Anyway.
GM/Delco unit.....

UP
green +
gray -


DOWN
green -
white +

The relay determines this but you can touch the actual wires to terminals on a battery to test.

 

[DMX]

Anyway.
GM/Delco unit.....

UP
green +
gray -


DOWN
green -
white +

The relay determines this but you can touch the actual wires to terminals on a battery to test.

It is an aftermarket antenna with a part# HA, HIA, made in Japan. I cannot locate a relay. The wires are Brown, White, Yellow. I will try the battery touch test to see if the antenna is at least operational.

 

[Antz81]

It is an aftermarket antenna with a part# HA, HIA, made in Japan. I cannot locate a relay. The wires are Brown, White, Yellow. I will try the battery touch test to see if the antenna is at least operational.

That could be the came as what I have in mine. (same wire colours anyway, and my car spent a long time in Japan).
If it is, wire it this way:
Up, Yellow -, brown +
down, Yellow +, White -

There was an additional relay in mine as the antenna would work in reverse without it (I swapped the motor polarity to remove this), but for you it shouldn't matter. (the relay was at the antenna). If there is a relay in your car for this it could be anywhere as it would have been fitted aftermarket. You can use any 12VDC DPDT relay for this. If it is working and you want to wire it up let me know and I'll draw up a diagram for you.

 

[DMX]

That could be the came as what I have in mine. (same wire colours anyway, and my car spent a long time in Japan).
If it is, wire it this way:
Up, Yellow -, brown +
down, Yellow +, White -

There was an additional relay in mine as the antenna would work in reverse without it (I swapped the motor polarity to remove this), but for you it shouldn't matter. (the relay was at the antenna). If there is a relay in your car for this it could be anywhere as it would have been fitted aftermarket. You can use any 12VDC DPDT relay for this. If it is working and you want to wire it up let me know and I'll draw up a diagram for you.

I completed the jump tests today and it is the same as yours and the antenna works well. The wiring leading from the antenna goes only as far as the park brake lever and I cannot locate a relay. Looks like the previous owner gave up on the installation. I will have to find a DPDT relay to make it work.
I would be great if you could do up a wiring diagram.
Thanks Danny.

 

[Antz81]

Ok, Diagram should be below. For the 12Vsw supply it can be connected to the antenna output of your radio (normally blue) if aftermarket, or if it's factory connect it to the switched supply to the radio. The 12V supply must be hot at all times. Any guestions just ask.

 

[DMX]

Ok, Diagram should be below. For the 12Vsw supply it can be connected to the antenna output of your radio (normally blue) if aftermarket, or if it's factory connect it to the switched supply to the radio. The 12V supply must be hot at all times. Any guestions just ask.

View attachment 23848

That is awsome! I have been sourcing a relay and there is many options but nothing in stock locally. Do you have Manufacturer and part# that you used in your application ?

 

[Antz81]

That is awsome! I have been sourcing a relay and there is many options but nothing in stock locally. Do you have Manufacturer and part# that you used in your application ?

Mine ame from the factory with a power antenna so i still have the factory relay.
Seriously nothing in stock? It's a common type of relay. Something like an omron LY2N with a 12dc coil should work.