My high speed internet was cut by construction, so I'm on 28.8

The blower motor in my wifes W126 stopped blowing.. I suspect the motor itself, or more specifically, the brushes. I located the motor and banged on it hoping it would spin, and make me sure that was the problem, but no such luck.

There are two wires going to the motor, a red, and a blue.. Both have voltage, and will light my test light. Can someone make some sense of that?? I expected to see a hot, and a ground. How is the motor grounded??

Help me help myself..

As always, thanks for the help..

Jay

__________________
89 300SEL Money Pit

92 Blown Buick Ultra Pimpmobile 220K and adding 1K per week

88 Wagoneer Slightly modified (Not for soccer moms)

04 Kia Sedona with every option... NICE

The blower is grounded by the blower regulator. It is like a huge variable transistor switch that responds to a 1-6v control signal from the pushbuton controller

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

Sometimes this car baffles me sometimes..

With all of the blower motor, and the big heat sink looking thing laying in the floor, I can't get any voltage any whwere now. Is there an easy way to troubleshoot this problem. I'll be out of town all of next week. So, tomorrow is my only hope, or my wife will need to rent a car for next week.

__________________
89 300SEL Money Pit

92 Blown Buick Ultra Pimpmobile 220K and adding 1K per week

88 Wagoneer Slightly modified (Not for soccer moms)

04 Kia Sedona with every option... NICE

Yes it is simple. The blower has two wires one is hot and the other is ground when the blower works. What isn't happening?

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

Steve.. You should have said... Drum roll please.... "Did you locate, and check the BLOWER MOTOR FUSE you dumbass!!!"

Turns out, there is a blower motor fuse located outside of the fuse box right in front of the master cylinder in a little black box.. It had cracked in the middle and was making enough contact sometimes to show a voltage, and sometimes not.. But not enough to turn the motor.

For now.. The fuse is a 14 ga wire, until I have time to get by the MB dealer..

The intermittent/poor connection is always the most baffling one to solve..

Thanks for your help..

__________________
89 300SEL Money Pit

92 Blown Buick Ultra Pimpmobile 220K and adding 1K per week

88 Wagoneer Slightly modified (Not for soccer moms)

04 Kia Sedona with every option... NICE

Steve:
Regarding Jay3000's observation of both wires being hot at the blower motor, does this suggest the blower motor regulator is the problem (no ground)? Does the normal (one hot and one ground wire) apply when the blower motor is OK but turned off, or only when it is on and functioning correctly?
Also is there an easy way to trouble shoot the regulator short of replacing it?
I have an 85 300SD and had the blower motor replaced with a used one (I gambled and may have lost). It worked great for three months, then started working erratically and then low speed only, and now not at all.
I was hoping it was the fuse, but despite various suggestions as to where to look, I haven't found the "outboard" fuse. Does this model have one? I noticed it is listed on the fuse box list.
Thanks for any and all replies.

__________________
1985 300SD CA (low miles 180k)
1977 300D (RIP)
------------------------------------------------

In theory, there is no difference between theory and practice. But in practice, there is.

I can almost guarantee you that somewhere the motor will have a 20, or 30 amp in line fuse.

Mine was located in a little black box in front of the master cylinder just outside of the fuse box.

I can't help you with the other questions. Once I saw the cracked fuse, I did not analyze it any further. I'm just happy it didn't cost me another $200 which seems to be the average rate for something that's wrong.

Back to top for ya.

Jay

__________________
89 300SEL Money Pit

92 Blown Buick Ultra Pimpmobile 220K and adding 1K per week

88 Wagoneer Slightly modified (Not for soccer moms)

04 Kia Sedona with every option... NICE

Originally the fuse was in the box, but they melted many a box so even ones origionally in the box have been moved to the fender. wE have done a bunch of them.

The 85 doesn't have the blower regulator like the 86 on car does. It has a separate controller and a resistor pack.

In the first testing done to Jay's car his first description caught me off guard and thus I didn't suggest the fuse. What was happening was that he evidently didn't have a load set on the system and the fuses get a hairline crack. The fact that he had power on both sides should place the blame on the regulator as it is a variable connection to ground naturally. What in fact must of happened was under no load the fuss passed voltage as load was applied it became a circuit breaker.

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

I've had luck with the following non oem options:
Replace motor brushes rather than buy new unit. (Sounds like you PeterT)
Replace oem control with home-made speed control (nice, but not really worth the effort.)
Use relays or transistors to ease load on ailing oem speed controller, or maybe wire relays/tranz to activate via A/C and heater.
Bypass oem switch completely with simple toggle switch (easiest, but no speed control).

Just some ideas.........

Sorry, I don't have the working link. I'll go looking for it.

__________________
1987 300E
1967 Jaguar E-type Series I, 2+2

linkie no werkie