Blower doesn't work, blown fuse? - '78 300D - PeachParts Mercedes-Benz Forum

rgnprof · #1 01-21-2006, 11:24 AM

I have read through every post I can find in the archives, but I can't find one that deals specifcally with my car (I am new to the diesel world). The blower doesn't run at all and initially folks mentioned the ACC servo which I have visually inspected - it looks fine, no cracks. leaking, etc.

I have read about blower motor brush problems and blower motor fuse problems with similar models and I'm beginning to wonder if I have a blown fuse - trouble is I don't even know where the fuse box is located on this vehicle. Can anyone advise, any ideas?

Thanks, Ryan

TheDon · #2 01-21-2006, 11:43 AM

my knowlegde of chasis years is little foggy im still learning but on my W123 its right on the firewall by the brake booster thing.. .. if you were to sit in the drivers seat the fusebox on the W123 is in the engine bay right in front of where the steering wheel and a little to the left.. maybe i have a pic

W123 chasis 300D-T

it has two round plastic knobs that screw into it .. its a pita to get the cover off.. they engineered these cars around the fuse box my friend

Whiskeydan · #3 01-21-2006, 11:52 AM

You should find the fuse box under the hood, kinda between the brake booster and the left hood hinge. Two small knobs hold the cover on if it still has a cover.
Clean the fuse contacts, while your there, with a scotch brite pad. They tend to oxidize.
Be carefull putting the cover back on. Its easy to snag a fuse and knock one out.
Or, just leave it off and send it to me. I could use one.

Wouldn't hurt to pull the blower and clean and lube it.

TheDon · #4 01-21-2006, 11:54 AM

putting those fuses in was hard.. they sure did pick a prime spot for the box

Whiskeydan · #5 01-21-2006, 12:01 PM

Quote:

Originally Posted by TheDon

putting those fuses in was hard.. they sure did pick a prime spot for the box

Use a small flat blade screwdriver to hold one contact back while you carefully place the fuse into place. Once in place, rotate the fuse a few times to make sure its seated and help "hone", "burnish" its new connection.

Don, Whats the small plastic filter I see?

TheDon · #6 01-21-2006, 12:14 PM

i have no idea what that small plastic filter is.. its on a vac line i belive so im not going to touch it. but according to my friend with a civic it adds like ten horsepower yo

rgnprof · #7 01-21-2006, 12:23 PM

Thank you for the quick responses!

How much trouble is it to pull the blower motor? Can anyone provide R&I steps? Thanks.

Ryan

white500se · #8 01-21-2006, 02:54 PM

Quote:

Originally Posted by rgnprof

Thank you for the quick responses!

How much trouble is it to pull the blower motor? Can anyone provide R&I steps? Thanks.

Ryan

It's pretty easy to do. It's located in the passenger footwell area so you have to start by removing all the carpeted pieces under the dash. That will leave 1 more trim type peice to remove all are on with phillips screws. Once these are off remove the hose that goes between the center vents and the passenger vent and you'll see the motor and housing. The motor is held on with 3 8mm bolts. I find it easier to remove the top one if you take out the glovebox first.
Once the screws are out just pull the motor out of the housing. Leave it hooked up and turn the key, I found that I could rotate mine around and get it to start working again. It always stops again when it's installed but if I hit it with a ratchet I can get it to start up. You can always try that before you remove it- after getting everything out of the way just hit it afew times and seeif it starts spinning again. Someone else here can provide info on what to lube it with I'm sure, I've tried a few things but nothing lasts.

John

'80 500SE AMG (yes,it's a real one)
'80 300SD

rgnprof · #9 01-22-2006, 02:24 PM

All the fuses look fine - so I will probably be tackling the blower motor next. I can feel heat when the thermostat is set in the 70's, but I'm just not getting any blown air.

Thanks for the help.

Ryan

rgnprof · #10 01-24-2006, 06:31 PM

OK, I got to the blower motor and when I just banged on the casing - not too hard -the motor started, but it only runs when the climate control is on Defrost. I push any of the other buttons - bilevel, high, low, and the fan shuts off - push the defrost again and it starts to run. Any thoughts?

Ryan

Diesel Giant · #11 01-24-2006, 09:26 PM

The filter in the vacuum line is a protection to the vacuum system to keep oil from migrating into the system when components fail such as the shut off solenoid and vacuum pump. If you look on cars that do not have that filter then you often see oil residue in the vacuum lines. The oil will soften and eventually cause leaks by breaking down the plastic.

The filter is suposed to catch any oil that would get in the system.

Lycoming-8 · #12 01-25-2006, 12:14 AM

Usually when thumping the blower gets it started, the problem turns out to be worn motor brushes. There have been several threads on this, covering how to find brushes and replace them. Appears there are at least two brands of blower motor, and rebuild luck seems to vary with the type found in the car.

rgnprof · #13 01-25-2006, 08:45 AM

Thanks for the replies - I have read through the threads that discuss the brush problem and I am planning to pull the motor this weekend. But, I don't understand Diesel Giants's post??? I guess you're saying the problem with the blower only working in defrost mode is a vacuum problem? Where is this filter located and can I change it out (again, I am new to these diesels cars, not unfamiliar with vacuum control though).

Thanks, ryan

dannym · #14 01-25-2006, 09:15 AM

I believe DieselGiant was just explaining the function of the filter. He never associated that with your fan problem.
Your problem is more than likely with the motor/brushes. It does not sound to me like a vacuum problem or it probably wouldn't work in defrost

You can look for a new motor Bosch part #130 111 001 they go for around $100.
You may be able to just replace the brushes if the comutator isn't worn down.
Brushes can be found for around $20 a set.

Danny

rgnprof · #15 01-25-2006, 03:13 PM

Again, thanks for the help. I pulled the motor over lunch - no problem with the fan spinning - bearings seem ok. I have searched through the posts on this board and I'm not sure how to proceed. My motor looks like it is a sealed unit and I'm not sure how, or if I should proceed. I'm not exactly sure how to take it apart from this point.

Also, if it is the brushes where can I get the right ones for this motor?

ryan