Antenna trouble...

[MercFan]

Happy Thanksgiving all - my wife is signaling me to step away from the computer (hehe) but first, I need to ask for some advice:

The antenna in my 300SDL had been making funny clicking noises, so I pulled it out, disassembled it to find that the mast was stuck and would not fully extend. Cleaned everything out and lubed it thoroughly. Re-essambled and was pretty pleased, however upon reconnecting to the plug in the trunk it does not respond at all no matter what I do... I've placed a voltmeter on all of the terminals in the plug and I see 12V on one of the prongs, but the voltage is constant... It's not even sounding like the motor is trying to run - it's acting like it's not even getting the signal. I recently pulled the battery completely out to re-charge... not sure it's related, but it may be.

Would be nice to have a wiring diagram to figure out which prongs should get energized when the antenna button is pressed (up/down) - any help would be appreciated.

Thanks and Happy Thanksgiving Day - hope you get some good eats today.
James

[WDBCB20]

I Think my '85 has the same Auta 6000 EL as the SDL. And I'm having the same issue.

A crude test I did so far was applying voltage directly to the terminals on the motor circumventing the electronics of the control module circuit board thing to see if the motor worked. It did. So my problem is in the circuit board. Keen to hear what you find.

[Yak]

Maybe dirty/corroded terminals. Mine was iffy after I re-installed it. If you're only getting +12 on one of the plugs with the radio on and trying different settings on the antenna switch, I'd guess the switch is the culprit. It interrupts power to the other three wires in the plug. It's straightforward to disassemble and clean. There's a thread somewhere on that. Just be careful of the springs and the tiny ball bearings.

Some pin-out info here:
http://www.peachparts.com/Wikka/W123AntennaMast2

or here:
Accessory:

and some hard-to-see diagrams here:
Keeps blowing fuse. A little help?

[MercFan]

Thank you much - will study it. I dug out the following diagram - see below - it's for the W126 1986-1989, so I think that's it.

I'm going to hookup a stand alone 12V battery: #2-Positive; #6-Negative, then run a jumper from #2--->#1, or #2---->#4. I'm hoping that #1 and #4 will produce forward and reverse movement (if the circuits are ok). More on it tomorrow after testing - good night all.

EDIT: Yes, the above pin configuration is correct - confirmed. The antenna tends to stay in a default retracted position. Appying 12V to either pin#1 or pin#4 causes the antenna to extend the mast as long as you maintain the voltage to the pin. Removing the voltage from either pin causes the mast to retract back into the default position. Those are the results on the work bench, now let's see how it will behave in the 22 yr old car when re-installed...

FYI - I did observe a short in the circuit board that I have probably caused before when cleaning or re-installing: I had two resistors bent towards each other in such a way that their exposed wires were touching one another - I don't know if that's THE problem I was having but I'm sure it wasn't helping.