Antenna not extending properly
 

I have a 380SL 1985 which has a problem with the antenna. The antenna does not move when the switch is placed in the middle location. I thought this should extend the mast to a half way point. I replaced the switch but this did not fix the problem. Any ideas on what is wrong and how I can fix the system?

Let me go check my '85.......

OK, my antenna works as you stated it should. When I have time this week I'll take a look at electrical values at different points to help troubleshoot.

If you have suggestions let me know.

Rick,
Thanks for the post. At least I know I am reading the manual correctly. If you do find any ideas for me to check send them my way.

If it works like my '89, it should extend partly (but only when the radio is turned on) with the switch in the center position, and fully when the switch is in the left position. If it does the latter, then you may simply have dirty switch contacts.

I think he replaced the switch with a new one.

Yes, I replaced the switch and it didn't help.

Without looking at this I'm thinking there is some type of timed circuit or limit switch.....I'll most likely look this weekend.

Below is what I found when checking voltage to the antenna connector. Use a Voltmeter to check values at each socket in varying states of operation. The number 6 socket is ground, so your negative (black) Voltmeter lead will be here throughout the test.

The results of test numbers 3 and 4 will tell us alot regarding your center position problem. Notice that socket 1 does not have power when the antenna switch is in the center position.

BTW, the test yielded the same results with the key in either the Accessory position or in the On position.

Let us know how it works out.

Connector in place:

Connector removed / Underside:

Test:

Rick
Thanks for the help. I tested all the combo's that you illustrated in the last post. Two places you mentioned the number 3 as being hot. I think you meant the number 2 socket, because the number 3 is empty. All my tests agreed with your's except the fifth test. You showed a number 2 socket as the only hot socket. I had the number 2 socket and the number 5 socket hot.
What do you think? Does the fifth test difference mean anything or do I need to bite the bullet and get a new antenna?
Thanks again for the extra effort you put into helping on this problem.

Duh, I'll recheck the number 3 on my cahrt.

Regardless. If the number 1 socket is hot / not hot on test 3 and 4, respectively, then I'd look at the motor circuitry.

Might be time to disassemble.

BTW, what's the sense of a half lowered mast? Is it that high?

I'll replace the chart with an accurate one for future reference.

While you're in the trunk can you help me solve this mystery?

http://www.peachparts.com/shopforum/mercedes-benz-sl-discussion-forum/77474-someone-please-check-something-their-107-me.html?highlight=light

I will look into the antenna internals this weekend...stay tuned.