So on my way to the coast last night, about an hour into my trip, I began to smell something coming through my vents. I pulled over first chance I got, and realized my blower motor was not working. I should mention that I believe my evil servo has been "bypassed" since I have no control over temp, just fan speed and direction, as in defrost, bi-level, high and low, and always hot. So upon inspection I noticed the smell seemed to be coming from the blower motor(under the glove box). The exterior of the motor was extremely hot to touch, painful even. When I turn on any of the heater settings, I can see the ....well I don't know what its called, but it seems vacuum controled, and is to the left of the blower motor. Anyway that part "opens" or "expands" like it always does but the blower does not kick on. I disconnected the cable to the motor and finished my drive. I do still get hot air in the right places when I select any of the settings, but only at driving speeds.

So.. is my blower motor toast? Is it normal for it to be painful to touch? Has anyone ever had their blower go bad, accompanied by a burning smell, almost sweet like coolant.

You can do some more diagnostics. Put 12 volts to the fan and a ground and see if it runs. These motors do wear out. I have a thread on here describing how to replace the brushes on the 116 blower motor.
There is an amplifier behind the glove compartment that can fail stopping the blower. It can fail if the auxilliary water pump seizes and draws too much current. Fusing the aux water pump is a way to avoid this problem.
Blower will not work if the main vacuum switch (green behind the glove bos) is not actuated.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Last first. Sweet smell is coolant leaking into heating ducting or may actually drip into passenger compartment. The leak could be from a loose fitting of heater hose to metal tubing at connection ( You should be so lucky). Heater core may have burst/opened up a crack somewhere. Will require getting a lot of stuff away and finding the core. If you are short on patience and long enough on dough you may wish to have an experienced person (handy owner or professional tech) look for you. Trade frustration for dough.---or whatever.

Motor smell/hot motor could be a fan (squirrill cage) stuck in the housing or a very tight/siezed bearing keeping the motor from turning and heating up while standing still. Something (very worn bearing) may have shorted the armature(part that turns) against the field (the stationary-outside windings). Getting the fan out is not a big job--a couple of short screws. Take the fan motor shaft and wiggle it to see if it seems loose in the bearings. See if it spins freely or sticks somewhere. Identify that . If you don't see anything out of whack, touch the wires to a battery and see if it turns. If it doesn't but otherwise spins freely, your brushes may be worn out (but, in that case there wouldn't have been current wanting to flow and the motor getting hot). Seems as if current wanted to flow but something was preventing the motor from turning. See if that 10mm wrench you lost found it's way down a vent tube and stuck in the squirrill cage fan. My motor on my 6.9 had worn the commutator (segmented copper thing the brushes ride on) down by a brush holder getting loose and grinding on it. ( Still need a serviceable but affordable replacement) I made up a couple of brushes by cutting down some hardware-store ones and I chucked the armature in the drill press and did some file and sandpaper lathe work on the commutator to get by but it soon gave up anyway. These motors are pretty stoutly made and even elementary maintenance keeps them going a long time. Bearings are permanently oiled but can wear. Brushes wear after a zillion turns and can be refitted. The rub is usually getting the motor apart. I bend the tabs out and use my mig welder to reassemble. Maybe even JB weld would do in a pinch. See if getting it out and looking at it & fiddling will show you something. Then get back to us.

Sparky

Great suggestions guys! Thanks. As far as a coolant leak, I don't think that's the case, since the smell went away after I disconnected the power supply to the fan. And like I said, I am still getting lots of hot air in the car while moving down the road, and there is no more smell, and the blower of course is not even warm. I will remove the blower motor when I get the chance, and see whats going on.

When you're moving, the air will circulate without the fan on. do you hear a fan sound?

A small leak of antifreez wil dissipate but may come back. Just something to think of.

good luck---
Sparky

No fan sound. I had another W116 that had a non-functioning climate control. No fan, no change what so ever when selecting one of the heater settings. Where as my current W116 does change its air output based on the settings selected, only it has no forced air, so I assume the problem is simply an inoperable blower motor.... hopefully