Thread: Wiring help: 12vdc Power antenna & GM relay

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Hope someone can help me. I bought a 12vdc power (up/down) antenna https://www.surpluscenter.com/item.a...-1750&catname=. It needs a GM relay to operate. I bought one:

The bottom prong is #30, Left is 86, Right in 85, Top is 87 and middle is 87Q.

There are three wires coming off the antenna white, gray and green. I believe white and gray are the ones that make it go up and down. Green? No idea.


I will power with a 12vdc wall wart (and control off/on with a motion detection light with the plug socket screwed in where the bulb goes).

Here is the paperwork that came with the antenna:



I need help getting it wired so it goes up and down and getting the power to the right prong on the relay. Any help would be appreciated. Thanks.

Do you really have to use the relay if you're obviously not using it in a car?
I would think two of those wires are the power wires. Couldn't you just experiment hooking two of the wires at a time to the wall wart?
I bet it would work , as long as the wall wart has enough amps to power the antenna.

Boy you are asking a lot here.

You have to figure that some kind of limit circuit is involved here. Since this is a device that is normally controlled by the radio, we can assume that the relay is energized by the radio when it is turned on. But once the antennae reaches it's full height the relay must open or the antennae motor would burn out. So likely one of the three wires is likely offering some kind of limit switch controlled circuitry. So the relay is likely a double pole double throw relay that once the antennae reaches it's limit on eithe extension or retraction the relay then only allows movement in the opposite direction. So when you turn on the radio the relay activates to extend the antennae. Then likely one of the wires to the motor goes open and that stops the motor. But the other reverse polarity circuit is active. Whe the radio is turned off that resets the relay to normally clooed and that side of the really is wired reverse which retracts the antennae. So what you need to make sure you don't do is connect the positive and negative to the two wires that I am betting are connected to each other. That would be a direct short. So that is why the volt ohm meter will help. But worse case you can just use a test light if you have one. If you want some help on this then PM me. I can help you on the phone. I am a tech and I help people all the time to diagnose problems.

Good idea, but I am betting that two of those wires are a direct short.

If memory serves (big if - I haven't messed with this stuff in years), to raise the antenna the white wire is +12v, the green is ground, and the gray is open. To lower it the green is +12V, the gray is ground, and the white is open. The antenna has built in limiting switches, so you won't have to worry about that. Like I said, it's been years since I worked with one, so proceed at your own risk (and if you let the magic smoke out of it, don't say I didn't warn ya! )

My guess and it's only a guess but I bet the motor stalls at the end of it's travel (just like a power window). A power window stalls without the use of a relay and this motor could also but I'm not 100% sure on that.

Just another guess but I would think the 3 wires is 2 hot and one common. One hot to power the up and the other hot to power the down and the relay is the used to switch the power.

From looking at the motor it doesn't look like it has any circuits in it that will be ruined by testing it like Dave said. The worse thing that could happen is you mess up the wall wart by connecting 2 hot wires together. Personally I would use a car battery charger or a car battery to test it.

Here's another thing I just thought of while I was typing...the wires is a positive, negative, and a ground. It might need a ground to keep it from interfering with the radio and the relay is the switch...just a guess.

Best bet would be to stop by a local garage, take it in and ask. Go in and expand what you are using it for (to make a Halloween Prop ) and I bet someone will help you find out how to get power to it.

A search came up with this link.

It might be easier to find the GM relay that was designed to be used for this - the one you show in your first post won't work on it's own. You should be able to get one from your local Chevy dealer - those antennas were used in quite a few different GM models.

Thanks everyone. I tried wiring the wallwart to the wires on the antenna, but it didn't move (and I heard no sound). Might not been enough amps. I'll try a 12v battery charger tonight.

"Magic smoke" I like that....and have seen it before.

I would be green would be ground or negative. Then the other two wire would be positive. White might be to raise it and grey to lower it.
So neg to green then positive to white to raise it. Then remove power from the white and apply it to the grey to lower it.

Function,

You would need -12 volt to lower the antennae. Where would you get -12 volts?