So it's getting nice and warm these days and I want to get my A/C fixed, but the only problem is that even if I fix my A/C my blower motor still has a problem that I can't figure out.
Oh hot days it will blow for a few minutes and then stop dead. After a few seconds it will come back on, but only for a few more seconds then it dies out again. It does this on any and all settings with and without refrigerant in the car.
Any ideas?

__________________
1992 300D OM602

Ben

Advanced Search (on this site) under [Blower Fan] + Arthur Dalton's name yields the MOST info on everything!!!

[LOTS of GOOD reading there]

'May be time for a new fan (or Brushes).

The System consists of the:
Fan,
Fan resistor/controller
(Which is controlled by differing voltages by the CCU unit)

Blower Fan R+R with pictures:

PeachPartsWiki: Blower Motor Removal

__________________
'84 300SD sold
124.128

On your left front shock tower there should be a black case about 1 x 3 inches. Under that case is a strap fuse. This is the power feed to the blower controller. Confirm this fuse is good and the screws are tight. You might have a hairline crack in the fuse or a slightly loose screw that passes power ok when cold, but when it heats up under the current draw of the motor, the fuse opens up.

Edit: This fuse is only live when the key is in II. I previously thought it was live all the time.

Also M-B has made available the factory service manuals for the 124, go to startekinfo.com and look under workshop resources.

__________________
The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

Is it the original blower motor? If so probably nearing the end of its life.

__________________
14 E250 Bluetec "Sinclair", Palladium Silver on Black, 153k miles
06 E320 CDI "Rutherford", Black on Tan, 171k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver, 142k mi, wastegate conversion

19 Honda CR-V EX 61k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

I agree but a crack in the fuse can definitely cause the symptoms described.

I do agree the OP should pull the blower motor and check for proper operation and lube it while it is out. Probably also 20 years of trash down in there too.

(Makes me think, another project for my to-do list...while I am at it, since the wiper has to come out, need to look at that too.. but I digress.)

I would hate for the OP to go to all the trouble of pulling and servicing the motor, only to have the problem still there due to a cracked fuse.

__________________
The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

Is this the fuse you're talking about? It seems to be in proper order, can't see any cracks and the screws are nice and tight, but I suppose a hairline crack can be invisible. I'll get a volt meter on it tomorrow.
I replaced the blower motor with new one probably about 5-6 years ago.
Although that link didn't work, compress ignite, I performed the search with your criteria and I've been reading through some stuff. That Arthur Dalton seems to be pretty knowledgeable about this kind of stuff. I'll keep reading. Thanks guys!

Attached Thumbnails

 

__________________
1992 300D OM602

Ben

That is the fuse. It is aluminum; the screws are plated steel. Corrosion can sometimes occur. I use the anti-corrosion stuff that electricians use when they join copper and aluminum wiring. In any case, the problem is more likely worn brushes but the fuse is a lot easier to get to so might as well check it first.

Jeremy

__________________

"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

The result !

This forum is an Ongoing Education Process for all.

__________________
'84 300SD sold
124.128

Well the voltmeter I was using was giving me all sorts of funky readings, I think that it's messed up. I'm going to try to get my hands on a different one.

Another thing I forgot to mention is that in cold weather the fan stays on all the time. I get heat in the winter just fine, it's just in hot temperatures that it will stop working.

I'll also look into cleaning the fuse and screws. Just FMI (for my info?) where can I get a new fuse like that?

__________________
1992 300D OM602

Ben

Pelican can sell you a spare fuse. Always good to have one put away in the car somewhere.

__________________

"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970