Troubleshooting 380SE Climate Control

[donbryce]

Background: Last year, I had a new condenser installed and the A/C system converted to some hybrid refrigerant like 134A. It cooled all last summer and this one just fine, up until about a month ago. We had heat too, and all buttons worked as they were supposed to, including blower speeds, flaps, etc..
The Problem: At seemingly random times, after starting the car, nothing happens from the system. None of the buttons will do anything, the blower doesn't function no matter what button is pressed, or where the temperature wheel is set to. In other words, no heat or A/C. If you press the buttons, you can hear flaps opening and closing, so I suppose the vacuum lines function.
So we go to the mall or whatever, turn it off, then awhile later, on startup, everything comes to life again! A/C or heat depending on what the temp wheel was previously set to.
I'd thought that not turning it off (far-rightmost button) would 'fix' this, as it seemed to return to normal on startup if the system settings were left alone, but alas, it failed twice to come alive yesterday and the off button hadn't been touched.
Does anyone have an idea what system component(s) is/are the likely cause of this erratic behavior?
I checked the OVP relay and the fuse is OK. Likewise all the fuses in the box. It does blow cold air when it works, so I assume the charge is still up to proper level, and the blower motor works on all speeds, again when the system kicks in.
I don't want to waste my time or money chasing down every possible source, but would appreciate a few pointers on what would be the 'top of the list' things to test.

[TX76513]

Don, I am going to stab at this from the outside from some personal experience. When this happens slightly wiggle your ignition key and see if the blowers come on. If so - it's time for a new ignition switch.

[donbryce]

All I can say is WOW, you are right on the $$! I went out Friday and it started right up, then the blower came on like it should, so I wasn't sure if that was the issue.
We were away on the weekend, and I just went out and tried again....this time, I could hear the flaps changing, but no blower. Then, reach over and wiggle the key - Presto, all is as it should be. Again, THANKS VERY MUCH!
I remember now that I got the key stuck in the ignition, once, about a year ago, and I guess that would've been my first warning, and this is my second.
Hope I have an opportunity to help you out someday, but in the meantime, I'm once again grateful that this forum is here and guys like you are there when needed.

[TX76513]

Good deal - You might want to plan on changing the ignition - or if you are unsure about that read some of the post about stuck ignitions, that will convince you. It's a warning sign.

[woodman72]

Hello from a new member!
I have a very similar problem with the Climate Control on my '84 380SL. I also had the system converted to R134 about a year and a half ago. Up until about 3 months ago, everything was fine. I then started having a very similar problem. Now, when I attempt to turn on the climate control, nothing. Sometimes, the defroster will come on, sometimes not. A few days ago, I removed the center dash panel and unplugged the two 12 pin connectors. When they are plugged back in, I can hear what sounds like relays (plural) clicking. I then tried again and the blower came on and worked at all speeds. However, the compresor does not come on, so it blows hot air. I have had problems with bad or corroded connections on several items (the car was previously owned by an older man and probably sat idle for some time). I tried it again today and the blower no longer comes on (as well as the compressor). I have removed and reinserted all of the relays that I can find with no results. The only connection I haven't checked yet is the connection to the compressor.
I have a subscription to AllDataDIY, but their information is extremely limited on any subject. My Chilton manuals are also severly lacking in information about the climate control. I have worked on cars since I was young, but this has me baffled. My feeling is that the control unit (pushbuttons) is bad, but at the price they are asking for this part, it would be foolish to replace it and just hope that fixes the problem.
Any thoughts or suggestions would be greatly appreciated. FYI...I tried jiggling the key, as already suggested, but this did nothing.
Thanks!
woodman72

[donbryce]

Do a search on climate control. There are lots of threads with all the info you'll need to pull it out and re-solder the connections. I've got a new tape for the temp wheel on order, so plan to re-solder and do a general R&R on the pushbuton unit while it's out. I think your problems are in this unit's connections, from what I've read anyway.

[gmercoleza]

Where did you order the decal for the temp wheel?

[donbryce]

Originally Posted by gmercoleza

Where did you order the decal for the temp wheel?

It took a few calls and a bit of friendly BS, but I found a dealer parts guy who helped me look this little bugger up in their system. It's called a 'GUIDE SIGN', and for the control unit that I have (126-830-02-85), the part number is 124-821-29-67, and costs $5.95CDN at the dealer + postage.
I've been doing some research here, and it looks like replacing this tape will entail removing the complete unit and also disassembling the wheel section itself. If I'm going that far, I'll certainly resolder the connections too, even though my CC works fine.

[lesrrt]

Don is correct. Take out the acc and resolder your connections. Cured all the gremlins and the 134a has held for 3yrs now.