1991 350SD A/C acting a *little* strange...
 

When I picked up my car from my mechanic after having the GreaseCar system installed, the A/C ran just fine. The next time I drove the car, it took a few minutes for the A/C fan to start. There was icy cold air oozing from the vents for a couple minutes, then the fan kicked in and worked just fine from then on. It has done that a couple times since then, too. Is this something common? Has anyone seen this before and did you find a solution?

Do you think there could be a solution to this problem? It's a real pain to start the car, start driving in 100F heat, and then the A/C comes on 10 minutes later driving down the road! Actually, the A/C is working just fine - you can feel the icy cold air oozing out of the vents - it's the FAN that won't work immediately! Weird, huh?!?!?

Found a potential cause of the problem...
 

Okay, I took my car to my mechanic this morning to check on something unrelated, but I think we found the cause of my air conditioning/heat fan failure.

Apparently, the fan brushes get worn and stick - thus causing the fan not to engage as it is supposed to. The repair involves pulling out the glove box and going under the dash, so although it is not necessarily a difficult repair, it is pretty involved.

In the meantime, I have found a temporary solution - when driving the car, it seemed that the only thing that would cause the fan to suddenly engage was hitting some sort of bump in the road. So, I recreate that by smacking the under-side of the dash below the glove box with my fist. Sometimes it takes a couple good whacks, but voila - my fan comes on and I have cool air!:D

I might try to DIY this one since my mechanic's bills have been adding up - and especially since this does not relate to anything that I could BLOW UP!

I'll post more results here when I have them!

My old fan did that till it fried and died, I would just leave it on the "high" setting when I started the car so it'd get going when I bumped the dash, then I could slow it down. Later on the motor melted itself though, so I just got a whole new blower on ebay (aftermarket one) for like $135, its been working perfectly for years, and its VERY powerful....OEM ones are like over $300

I already found a replacement on eBay - I may just buy one to put in when I end up working on it. Thanks!!

Yep, here's one:

http://cgi.ebay.com/ebaymotors/Mercedes-blower-motor-A-C-ASS-W126-300SE-560SEL-300SD_W0QQcmdZViewItemQQcategoryZ33546QQihZ011QQitemZ320025193437QQrdZ1QQsspagenameZWDVW

Essentially any blower for a W126 chassis mercedes will work....there's some used ones on ebay too. Just search for "300SD, 380SE, 420SEL, 500SEL, 560SEL or 300SDL "blower" I searched under "300SD blower" but people list them under all different models of cars, all of those (including yours) use the same blower.

Thanks!!

blower motor changing
 

Is there any thread that goes in detail on how to change out the blower motor? Mine blew a fuse and then when I replaced the fuse it blew for about 10 seconds slowly and then stopped completely!!

Sometimes a worn ignition switch will cause the same symptom. When your fan does not come on gently wiggle your key left/right. Both my 126's had this problem.

My brothers 123 as well. Just turn the key anticlockwise after starting just a hair and the fan would turn on.

- Peter.