On our drive to Las Vegas this weekend (115 degrees farenheit), the blower fan unexpectedly stopped (blower fan on AUTO).

I couldn't get it to start up, so I switched off A/C (HOT!), re-engaged A/C button, nothing, then set blower fan to HIGH, and voila it worked.

Anyone have any ideas what's going on and how to fix, and prevent this. It would have been very SCARY to travel at 115+F without A/C in a black wagon.

Also, at temperatures above 105-degrees Farenheit, the A/C really doesn't blow very cold. Is this a design issue with the W124 (I'm using R134a)? Anyone to increase it's efficiency? Seems fine at 100-103F.

What did Mercedes do to the W124 A/C system that did Saudi Arabia and Middle East Duty?

Thanks in advance,

:-) neil
1988 300TE w/ 1995 C36 engine & A/C pump (R134a)

I had a 1991 300E with the same problem which became progressively worse untill it wouldn't run at all. The regulator and the fan motor went bad. Both require removal of the windshield wiper to replace. But since it could have been anything, it was the same cost to replace the major components myself in a hit or miss manner or have an expert fix it right the first time to the tune of about 500.00

I did replace the blower assembly about 1.5 years ago, but I did *not* replace the regulator.

I thought it might be the A/C slip failover, but the A/C continues to pump even when the blower stops.

Since the regulator is cooled via a heat-sink in the blower path, does it have a thermal cut-off if it gets too hot?

Thanks,
:-) neil