Here's what I've found so far - the air from the center vents in economy mode will run cool for a while and then kick over to full hot after running anywhere from 15 min to 1 hour.

From the climate control module there was a clickity click click click sound as you rolled the temp wheel. Sitting idle at a stop you could hear the clicking shorting sound and then it seemed to quit all together.

So on my long trip it was running cool for a while at first and I thought it was going to be ok... then it kicked into hot mode but luckily it was about 50 F outside so it was bearable with the windows cracked.

However, after many hours into the trip I noticed that the area around the temp wheel was ROASTING hot. I pulled the unit out today and the plastic cover of the climate control unit around the temp wheel side is melted and sunken in. The actual plastic frame around the climate wheel is melted and bent inwards towards the wheel so it rubs against it. What the heck!!

Apparently you can't re-solder these newer W126 (1986+) units like the older ones? I don't see how it would even begin to come apart like the DIY tutorial shows on the older units.

Does it sound like this could be a result of something else failing, or is just a total "meltdown" of the climate control by itself?

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(2) 1988 300 SEL W126