What stops the motor from running when the antenna reaches up or down position? I don't see any micro switches. Is it the box above the motor?More resistance trip the circuit?

 

Either the strain on the motor or the motor timing out.

 

Senses the current draw of the motor and likely a max timer as well. Once the motor stalls (stops against a load) the current draw will spike.

Why do you ask; replacing the mast?

 

Yes, mast cord broken. Removed broken piece, re installed and motor kept running. Thought I would check here to see if someone here knew the system. I assumed it was the increased resistance, but didn't take the assembly totally apart, just the cover to remove broken cord. Thanks

 

Did you install a new mass? Does it pull the antenna down and push it back up? How long does the motor run?

 

Ordered new oem mast($16.95 with shipping) on ebay. Not sure how long it would keep running, bu ran 40 seconds or so after running antenna up. I think the extra length of new unbroken cord will stop it. I think it ran off the cord as I can freely pull it up and down by hand.

 

Yea, something is not right. Get your stuff like that from FCP or iPD. I think you have a bad one. You should not be able to pull it up or down by hand because when the radio is off it goes down and you cant grab it.

 

Checked it out this evening,as I suspected,it ran off the cord when powered 'UP". I can re- thread it and it pulls antenna down properly.Turn on radio,antenna goes up and off cord. When I get the new mast in a day or two, I think it will work fine. Thanks all.

 

Yep, exactly! If you wanted to open up the antenna mtr box you'll find several inches or more piece of broken "cord" as you call it.

 

I thought you were having a problem with a new mass.

 

Received mast today, installed works perfect. This Ebay seller Rocks! OEM mast, $16.95 inc. shipping, 2 1/2 days, Wisconsin to Ca.! Thanks once again to all the responses....Russ