r129 sl hvac

[Les]

My '97 SL60 HVAC control display seems to have locked up and no matter which button I press the settings stay the same.
Cant change temp, fan speed ,etc.

Is this a symptom of the poor solder connections I have read about on other posts?
How do you remove the control unit to check?

Cheers
Les

 

[andy27168]

Hi,
I have the same/similar unit in my AMG, the "normal" fault is losing parts of the display or the display goes dim, mine at the moment does both. This can be due to a dry solder joint.
If it were mine and you feel confident to do it take it apart and run the soldering iron over every joint you can see, as it might cure your issues.
It is removed by standard stereo removal keys which can be bought from Halfrauds.
These units are very expensive to replace new, you can get them reconditioned I believe for around £200, can,t remember the company off hand but "try" somewhere like BBA reman.

 

[Doodle]

On the 129, you pop the stereo out and then put your hand in the gap to push the AC unit out. It needs the clearance underneath to allow the lugs to disengage, otherwise more likely than not you'll either sit there swearing a lot, or end up breaking something.

 

[Les]

Thanks for the pointers.
I will get the unit out and try going over the joints.
I suspect something more serious has happened with the unit now frozen and not responding to any of the buttons.
The display still works but nothing changes.

Les

 

[BTB 500]

Likely to be a 'mechanical' problem caused by hot/cold cycles / vibration / wear, I think. Cracked solder joints are common ... I had this in the climate control unit from our '96 Audi, this was the underside of the main PCB:

Re-soldered the joints and has worked perfectly since.