Air con odd problem

[Mr lestat]

Took my SLK out today for a 4 hour drive, it’s the longest I’ve been in it this year, anyway after about 3 hours or so the air con seemed to stop blowing any air out the vents at all despite trying all the settings available. After a 15 minute stop all was well again and it’s blowing strong and cold, a bit bizarre really. Any clues anybody ?

[Sheepshanks]

Sorry, can’t help but would be interested to hear if you get a solution as the blower fan in my 2005 C Class usually works, but sometimes doesn’t. It’ll go off during a journey then start working again, without the ignition being cycled.
No faults are showing on Star.

I’ve read the fan motor brushes wear out but then I’d have expected the fan would just stop working.

[Mr lestat]

This sounds the most plausible so far as it was on full for 3 hours and fan on high as the roof was off. Basically I overworked it ?

[Sheepshanks]

Just picked mine up from the indie where it was having an ABS ring and sensor replaced and they gave me the Mercedes diagnostic print outs and on the initial scan it did have a current and stored code for Blower regulator. It had cleared on the final scan but no doubt it will come back. Blower worked fine - it's on manual, I didn't dare interfere with it! - on the way home.

I'm barely using the car now so will see how it goes. Todays job was expensive enough and it looks like the regulator is several hundred pounds and I know the indie will want to change the blower motor too.

[Mr lestat]

The blower motor on mine was blowing away it just wasn’t coming out the vents at all on any setttings, fine now it’s thawed out a bit

[eldar]

Mr lestat said:

The blower motor on mine was blowing away it just wasn’t coming out the vents at all on any setttings, fine now it’s thawed out a bit

Check the drains by the front bulkhead are clear. If blocked the blower motor gets partially submerged and fail. Also gets the pollen filter damp and clogged.

[Sheepshanks]

Mr lestat said:

The blower motor on mine was blowing away it just wasn’t coming out the vents at all on any setttings, fine now it’s thawed out a bit

Pity you can't easily test that while keeping going as the a/c keeps running at reduced power for about 15mins after it's turned off.

It is an issue you see mentioned in hot humid climates such as Florida.