I have a 1991 300e. after my last service, my fan only works sometimes.

Sometimes it'll work right when i start the car, sometimes randomly starts after 15 min of driving.

sometimes it doens't work at all during a given day.

All fuses are fine, including the blower fuse

Some of the things i noticed is:

when the fan doesn't work, the control buttons like fan speed and blow options don't light up. Also the circulate fan red led doesn't turn on when i hit the switch.

My mechanic thinks it's the blower regulator. but how could it all of a sudden starting having this problem after last service. Makes me think something was messed up on the last service or something.

Let me know if you guys have any ideas. thanks

I'm not an expert, but I had a similar problem with (2) 300e's and (3) 190E's that I've owned. The way you described it, sounds like the climate control module is failing. This is the push button control unit and it has a microprocessor inside. The processor (computer) nearly always fails over time.

It's not user repairable. But you can find good used ones from Potomac German Auto in Maryland or Silver Star Recycling. Any large bone yard with Mercedes parts will have one or can locate it for you.

Best Regards,
William

You probably have already checked this, but just in case.....
On top of the left shock tower, there is an in-line fuse inside a plastic cover. The fuse is a flat piece of metal held in place by 2 screws.
I had a similar problem a few years ago and the dealer wanted to replace the computer/control unit. The mechanic already had the part in his hand, ready to replace it when a second mechanic told him to check the fuse.
Problem solved, I save a bundle.
JackD

hey guys,

Fused was checked and replace anyways. it turns out it as the control unit. I had to buy a refubished one. although i guess going to a junkyard may have been alot more cheaper.

You know where control unit is located, is that the chip itself?

__________________
Edgar
Warminster, PA

the control unit is the whole box with the push buttons. i believe the chip is inside.

WHAIR,

F.Y.I. I bought a functioning blower module on eBay last year for $32.00 + shipping. You might want to keep an eye on those auctions. You can find a bargain sometimes.

Be careful when removing the module, it's easy to damage the wood veneer trim.

William