Took panels off, gave blower a thump and it ran!

Pulled Blower and dismantled it. Brushes worn, commutator dirty. Bearings seem OK. No need to remove impeller cage on blowers with this Bosch motor

Will look at posts on replacing brushes & cleaning commutator. Alternatively see if surplus motor I posted about might fit. Or get a Volvo motor. Or buy a Uro blower. Decisions, decisions

Attached Thumbnails

   

__________________
Graham
85 300D,72 350SL, 98 E320, Outback 2.5

Go to the junkyard, buy a junk CCU unit for like $37 bucks, and then install it in your car. See if that helps it. That's what I did when my CCU unit crapped on itself.

You can also try to run a current directly thru the blower motor to see if it actually runs.

Edit: Looks like the problem has been identified.

__________________
1998 Ford Escort ZX2 5 speed - 279,000 miles My Daily

1992 Mercedes 300D 2.5 202,000 - Pure junk
2000 Mercedes E320 Black - 136,000 miles - Needs repair

Don't forget to grease the screw and threads on the spring compressor.

I don't know where to go with this, so I guess I will start here. 85 300D. I have read through this thread and tried a number of different things, but still do not have the blower working.

removed blower and connected direct to battery - works
tested voltage at plug while changing settings in CCU - 12V
fuses are all good

noticed pinging noise coming from blower regulator depending on settings. removed regulator, but cannot find any info on how to test to determine if it is faulty.

On a side note, noticed coolant level is extremely low. Will this prevent the blower from turning on? (i.e. car thinks the engine is cold)

Any help would be appreciated. Thanks!

Search for the electrical schematic which has been posted many times on this forum. It shows the inputs pins to the black plastic "blower relay box". Basically, each input pin commands a different blower speed by switching in different load resistors (box in engine bay). Insure that box gets a constant 12 V supply when blower is running. That was my problem (post above). I ran a separate fused power wire for it, straight from the battery, w/ relay, since the path thru the fuse box (and key switch?) can be unreliable.

__________________
1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans

So quick model question. I am still trying to find a fix for the heat in my 85 300DT W123.

Found a u-pull-it parts place that lists an "86 300" in their inventory. I called and the guy who answered wasn't much help (couldn't even confirm if it was a diesel). Normally I would just run over and check it out - unfortunately, this place is at least an hour away.

What I would like to know is, if it is actually a diesel, is there any chance the CCU and blower regulator module from a W124 would fit into a W123?

No. There are a LOT of differences between the W123 and W124 CCU's and the way they operate. You'd have to rewire the entire HVAC system.

__________________
Current stable:
1995 E320 157K (Nancy)
1983 500SL 125K (SLoL)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Gone and wanting to forget:
1985 524TD 167K (TotalDumpster™) [Definitely NOT a Benz]

On "heat" there will be a delay starting the fan until the coolant temp comes up. If you press the defrost button, it should override that and force the fan on high.

Pressing the "Max" fan switch also bypasses the blower resistor and sends 12V to the blower motor.

If "Defrost" or "Max" fan don't make the fan run, you likely have an open circuit or a bad ground somewhere since the fan motor is confirmed to work.

__________________
Current stable:
1995 E320 157K (Nancy)
1983 500SL 125K (SLoL)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Gone and wanting to forget:
1985 524TD 167K (TotalDumpster™) [Definitely NOT a Benz]

Thanks Diseasel3000. That's what I was thinking. Where would I find the ground for the motor? Also, could the open circuit be in the blower regulator (i.e. faulty)? Or would that more likely be a problem with the CCU?