A/C blower on my 89 300e works sometimes and doesn't sometimes

[scisco]

89' 300e A/C blower doesn't work sometimes. but It seems if I restart the car it will usually start working again. Is there something in the ignition that can cause the blower motor to work or not work?

[MB STARS]

Yes ignition switch will cause a\c blower inop also check the 30Amps fuse outside the fuse box.

I have seen this be attributed to the ignition switch on 123 cars but have yet to see this the culprit on 124's. That doesn't mean that it is not the problem.

Two other things that could be the problem are worn blower motor brushes or a slipping serpentien belt. The 124 has a sensor on the a/c compressor that will shut it down if the belt slips. The way to reset it is to turn off the ignition and restart the engine.

Hope this helps,

[MB STARS]

The RPM sensor at a\c comp only will turn off the a\c comp not the a\c blower.

Yes, it's been a long time since I had this happen, it may very well not turn off the blower. I would suspect the blower motor brushes or the CCU. The blower is pretty well buried, but you'll have to confirm that it's getting voltage. If so replace the motor or find a way to replace the brushes. The ones I've seen have been locked up, not worn brushes.

Good luck,

[Jackd]

Possibility: Loose 30amp. fuse on the front/left shock tower.
Make sure the contacts are clean and the 2 screws are tight.
I almost had my blower motor replaced ($$$) by my beloved Benz dealer because of that fuse.
JackD

[FrankR]

There could be some confusion here between the A/C auxiliary fan and the climate control blower. I think you're referring to the blower for the heater/AC climate control.

I'm waiting for Adsit to ship a new blower to me for my 560SL now, but not because it won't run - rather because it's chirping.

Last year the blower would operate intermittently - sometimes not at all. I replaced the push-button control unit and it did the trick. I don't know what control unit you have in your car, but I'd suggest checking the input voltage to the blower.... that is if that's the unit you're talking about.

Good luck!
Frank

Frank,

I reread the original post and see why you think that there might be confusion, but at the end of the post he says blower motor.

Scisco,

I went through the blower motor routine on my 300E last summer and since then had forgotten about the bar fuse near the m/c. I would recommend doing as much electrical troubleshooting as possible before digging down to the blower motor. Begin by checking for voltage on both sides of the fuse. These bar fuses can look good but have a hairline crack from vibration that is difficult to see.

Good luck,