Hose locations on heater servo for 79 300D - PeachParts Mercedes-Benz Forum

jblueep · #1 01-07-2007, 01:40 PM

Hi guys,

I've ready many of the posts on the dreaded/despised chrysler designed heater (climate control) servos.

I got my 300D a few months ago and after repairing many items (glow plug relay system, speedo cable, rear axles, front brakes/calipers/rotors), and I'm getting around to the HVAC now.

When I got my car, 2 hoses were missing from the heater servo. I discovered this when I first tried the heater (while 60 miles from home), and all the antifreeze leaked out. Of course, the benz heated up immediately, and I was out in the country with no tools. I had to get towed home.

When I got home, I discovered the missing hoses and I simply connected the 2 ports together with a heater hose to stop the leak.

In spite of reading the other posts, looking the chrysler manual for the servo, reading my benz and haynes manual, I can't find anywhere that tells me where these two hoses need to go.

Can anyone send me a diagram and/or pictures to show where the hoses go to/from the servo? I can't find any other obvious open connections anywhere under the hood where the two missing hoses would be routed.

Thanks for you help,

Jason

jblueep · #2 01-07-2007, 10:56 PM

I think I answered my own question by finally finding a heating hose diagram in the MB manual.

I attached a picture in case anyone else needs this.

unkl300d · #3 01-09-2007, 10:15 AM

before you put it all together, you ought to remove the servo, flush the heater core, flush the servo and flush your radiator coolant. get all the gunk out.
esp flush the servo

in hopes that it is functional.
check your AC amp to see if it is not burnt.

retx · #4 01-09-2007, 12:04 PM

hey unkl300d. why do you suggest removing the servo for the flushing? i have issues with my heat in my 80 300d and was about to do a flush and coolant change today.

jblueep · #5 01-11-2007, 10:39 PM

Thanks for the tip unkl300d. I'll do that

unkl300d · #6 01-19-2007, 12:09 AM

retx, a fellow member faxed me a service doc on this system. It recommends removing the servo to flush it and also allow the heater core to flush.

sorry just got in from out of town did not see your post sooner.

xaliscomex · #7 01-25-2007, 09:54 PM

just replaced servo with aluminum servo, Got heat....then...observed leak at base of aux water pump, then got NO Heat. Never flushed the coolant or bled the air out...I have no heat and was wondering idf i might of damaged the servo with sediment...could it be my aux water pump....where should i start...