power antenna driving me crazy!


I have a 87 gn with 14,000 miles in excellent shape with the exception of the power antenna. It doesn't work and I'm no electrician by any means. I ordered a replacement from gbodyparts.com and when I received it I plugged it in to check before doing the install. Nothing! I searched on here and found schematics and troubleshooting guides from vortecbuicks and some others. I've been trying to follow steps to trace if everything from the radio through the relay up to the antenna is correct but like i said i'm no electrician. If anyone has ideas of things to check please let me know. Also are there other options if I can't resolve the power antenna problem such as fixed mast etc.?
I'll check tommorrow but everything under dash and hood is in like brand new condition . I'll let you know if thats an issue. thanks
With the radio OFF you should have +12 on the White wire and a ground on the dark green wire.

First check the white wire to a known good ground and it should read +12.

Next check the dark green wire with the neg. of the meter and put the + red usually meter wire to the battery + terminal.

If the meter reads +12 you have a good ground on the green wire.

First simple checks of the wires at the antenna.

The CIG/CLK fuse must be good (interior lights working etc.) for the antenna to work and the test to be valid.

Key can be off and radio off for the test.
Thanks for that reply Allan, & Louis I didn't know you had an electrical back ground.
We bench test every one before they leave here. It looks like your going to become an electrician. When Chris told me you had a bad 14,000 mile antenna I was skeptical. I thought maybe a bad relay. I actually had him searching for new relays today & ordered up 5 of them for antennas.
Ha! I'm definitely not electrician. LOL ---- I just remember what had happened to mine... One day working, one day not. Checked the book and looked at the ground and it was broken. Fixed it and the antenna worked as normal.
There's definately a chance it could be the relay or the feeds to it which include the ground.

A good ground is needed, and the relay is a DPDT reversing type so all the contacts need to work properly for the antenna to work in both directions.
My 12,000 mile car would burn the relay contacts.
If you leave your radio on all the time. As you turn on the key, it wants to go up. When you turn further to crank, it wants to go down.
When you release after the engine is running, it wants to go up. All that up-down-up causes the relay contacts to burn.
Pull the relay, pop off the cover and look at the contacts if they look pitted and burned, clean them with 600 grit paper.
Make little strips of 600 paper and pull them through the contacts while holding them closed. Do this until the get clean.
Leave the radio off until the engine is running and turn it off before you shut down the engine.
I disconnected mine since I hate the radio stations here in Chicago anyway. I listen to tape.
Thanks everybody so far. I'm going to double check everything out again over the next few days. The connections at the relay all look good,ground looks good and connections at antenna all look good. I've tried the voltage reading at all points mentioned above and they all check out. I'll keep working at it all let everyone know the outcome. It's a little frustrating. While I was playing I went ahead and installed new scanmaster and took it out for a spin. Thanks.
My car came with electric antenna ... I have had a new gm one in the box for 3yrs heard it was a pita to change
Between the white and green wires use a trunk light bulb #89 I believe with two wires attached (soldered usually works) to it.

It should light up like a typical trunk light bulb (not be dim) with the key off/radio off test.

If it isn't normal bright looking like your trunk light bulb would be in daylight, and is dim or faint or doesn't light, the antenna motor isn't gonna run.
The reason for this test is to see if there's any current behind those voltage readings you said were okay on those two wires.

Drawing about 1A current from the bulb lighting will test the relay contacts and the wiring further.