94+ electric Antenna Control Module...what actually goes wrong?

C

CaifanSC

SCCoA Member
Has anyone figured out what actually goes wrong with the 94+ antenna module? Essentially every 94+ car that I've had has developed at some point the dreaded "Click click" from the antenna. At first I thought it was an antenna fault...which was deceptively confirmed by the problem going away after an antenna change. I replaced the antenna in my teal car with a new OEM piece and problem went away...for a bit.

I picked up a replacement module from the junk yard to do some testing but given how frequent this issue is...i'm not too hopeful with this module. The wiring schematics show a fairly simple operation of the antenna (gnd, down input, up input) with no weird limiters so that to me says the antenna is probably not at fault. After a basic visual inspection I can't find any burned components or questionable soldering joints.

Trying to see if anyone has fiddled with this issue so I can piggy back on it...or else I would start doing some reading and fiddle with the spare module.

thanks!









 
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Looking at that PCB, I see no mechanical relays (which would be my first suspect in any often used electronic part that's been around for 20 years).
You could try reflowing each and every solder point (won't take that much time with an iron).

Here are my thoughts on possible suspects:
* While it could be the capacitors, none look blown.
* My next suspect would be that diode (black stick with a blob on it to the left of the white connector). I'd check that next.
* Then, I would check the solid state items. I suspect the thing below the diode is a solid state relay but it could also be a voltage regulator. Either way, it gets enough current to require a heatsink and that many temp cycles probably isn't doing it very many favors.
* Finally, I'd check the various transistors (smaller black items with a flat side and a curve).
* After that, if you still don't find the problem, I'd toss it :)

I doubt the actual chips burned out unless something shorted them out.
 
I had a chance to play with this today before it started pouring. I connected the module from the junk yard and at first i thought I saw an improvement. With the key in the ignition ON (not start/run) I turned the radio ON and the antenna went up and stopped where it needed to stop...no extra clicks. I thought SWEEEET. Then I turned it off and when it reached the bottom it kept clicking. After fiddling a bit more I noticed there was still clicking when the antenna goes up and the key is in the run position.

Going by the diagram and what I observed today the module will release a specific output depending on which power input is being received (START, ACC/RUN, HOT ALL TIMES).

S4gunn, thanks for the input...that gives me somewhere to start. My very first hunch based on my limited knowledge of electronics were those capacitors. Those tend to define how long power is maintained before 12V+ is added or released, but like you, I was surprised they are not burned or leaking. Let me know if you think of anything else. It's been way too long since my electronics class so I plan on going to town on this bad boy :). Bring out the soldering iron!

820, buddy...I duno, somehow I still don't think it's the antenna motor/mast. I was checking my rolling thread on the teal car and an OEM NOS antenna was installed in november last year. Although possible, i think it may be improbable for it to go bad so soon. Also considering with this new module in one "setting" has the antenna working as it should with no extra clicks (key ON antenna going up). Depending on how things go with module I may open up the antenna and check that toothed cable.
 
CaifanSC said:
I still don't think it's the antenna motor/mast.
Click to expand...

It's not the module, trust us. They either work or fail. You have a hardware issue. The ratcheting is the antenna's clutch...you can sometimes tighten the set screw, but if the ratcheting has gone on too long, there isn't much point.
 
Also the plastic toothed cable may have to be trimmed to correct length. If it wasn't then that could be the reason it is now clicking after such a short time. GM did have one good idea (antenna embedded in the windscreen). KMT would have the correct answer.
 
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Noted folks... I just found it really odd that a new antenna would fail that quickly...but there is one lesson learned through the years: trust the input from this board :). So I'll dig out the old antenna and take it apart. Check out that cable.

I guess my insistence is exacerbated by the fact that both the 94 & 95 are both doing that clicking noise at the moment...so i decided to finally see whats going on. The issue seems to be one of those burdens we have to live with (just like the window motor bushings), its not an if...its a when. I would like to manage it just like I do with the window regulators. If I can have a spare ready for the 'next' failure and then repair the part that is taken out...i'd be really happy with that :).
 
OK....bringig this back from the dead.

I just installed a NOS brand new antenna on the chameleon car. The old antenna did the "clunk...clunk" when it extended, and when it went back down. After installing the new NOS annena, it only does it going down...but....~~~! Why would a brand new annena have this issue? I really think the module has something to do with this.

has anyone actually looked into the module? I have a friend who is an electrical engineer. I may ask him for some assistance with this, but wanted to konw if the group has any input.
 
I've had luck with simply tightening the clutch and sometimes degreasing the housing when the issue was clunk/clunk.
 
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