Mercedes-Benz Forum banner

1 - 13 of 13 Posts

·
Registered
Joined
·
56 Posts
Discussion Starter #1
Hello all,

Zeroing in on the last of the $700 190e issues now that she's all smogged and legal!

Troubleshooting the infamous "heat out of the center vents and defrost even while on AC setting."

It appears on this car it is a compound problem:

Problem #1 was that the defrost flap was always open even when defrost was not commanded. Turns out that the defrost actuator had failed. Removed it and disassembled and verified that one of the diaphrams had broken (it's the dual position actuator).

Problem #2, heat still comes out of the side vents - not burning hot like the heater in this car can get, but fairly toasty. Just took off the vent screen below the wipers, and inspected the heater control valve. Good news is that it holds vacuum, and I can feel it actuate when I apply vacuum with a hand pump, and this makes the side vent air warm, but does not ever allow it to get cold like the center vents. When I remove vacuum completely (valve fully open), the air out of the side vents gets much hotter. I may replace this anyways since it's a $20 part, but curious if I still have a problem deeper in the machine.

This leads me to the following two questions for the forum:

Question 1: Does anyone know where to get the dual-mode actuator? 000 800 87 75 | 0008008775 | - | Mercedes W201 190E 190D GENUINE Vacuum Element For Defroster Nozzle Flap NEW | New-Part.com. It seems to always come up as no longer available, and those that still list it, when you contact they also say no longer available. There is a '93 model at the Pick and Pull I might be able to grab this weekend, but would love to just snag a new one.

Question 2: Does anyone know if the heater control valve is in 100% control of the heat in the car? In other words, if I apply vacuum (closed mode) to the valve, should the side vents eventually get cold, or is this more of a min/max valve, and if heat is still coming through the vent when I apply full vacuum, then some blend door somewhere is not operating properly?

Thanks as always to all of you!
~Bryan
 

·
Registered
Joined
·
2,171 Posts
I had the same problem on my '93 2.3, I was able to get a new dual mode defrost actuator to fix the problem.
I think they're hard to get now. Maybe someone else will comment.

Question 2: I applied continuous vacuum to the water valve until I purchased the new actuator. It stayed closed and all the vents blew out cold ac.
 

·
Registered
Joined
·
56 Posts
Discussion Starter #3
Hello @SKK230red,

Thanks much for the reply. I apply vacuum to the valve, and I can feel it actuate, and the air turns from hot to warm out of the vents, so based on how it behaves in your car, that must mean that mine is not closing all the way. It was a cheap part ($10 from RockAuto) and so even if that's not it, I'm sure the vacuum diaphram has seen better days.

The dual mode defrost actuator is another issue.. I will try to grab one from Pick and Pull and hope that it works. If not, i think I found somewhere that someone did a mod using a different actuator.

Thanks for your time!
~Bryan
 

·
Premium Member
Joined
·
375 Posts
I just removed one from my parts car for someone with a similiar issue. I think the part is no longer available so you wont be able buy new if that helps answer your first question. Ill let someone else help answer your second question. Ill be up north this weekend in San Jose area working on my 2.6 I think I will also be at the pick n pull let me know if you need any help.
 

·
Registered
Joined
·
1,382 Posts
Bryan,
I would concur with the others about the dual mode defrost actuator. A couple years ago I tried to order one but none of the parts houses were able to get it. The only option is to get them used from cars that are being parted out. I parted out a 92 2.6 last yr and used it for myself.
I actually tore another one down before and it's always the rubber bladders inside that tear. If you could figure out a way to rebuild the bladder, you could get it working again.

Heater valve is definitely an common failure point on these cars. My car has gone through 2 of them in 30 yrs. In both cases they didn't lose vacuum but they started leaking coolant.
Those rubber elbows on the vacuum lines are another common leaking point, they tend to split which causes leaks. Whenever there's a leak the system defaults to heat.
Use your hand pump to test all the lines. Start w/ the vacuum connections by the fuse box. If no leaks, then you'll need to pull the glovebox and test the connections at the switchover valve. Last year I found I had a leaky elbow there too thus causing the heat issue.
Good luck!
 

·
Moderator
Joined
·
66,861 Posts
I just replaced heater control valve that's inside the firewall. Mine was leaking coolant.
Some years ago, that same valve its vacuum line somehow got disconnected and I ended up with permanent hot air coming from the vents. Once I place the line back in, everything went back to normal.
Anyway, the part is available on Amazon for $19. Part number: 000 830 57 84
Good luck.
 

·
Registered
Joined
·
56 Posts
Discussion Starter #7
Thanks to everyone! I was able to hit Hayward Pick-N-Pull a week ago Saturday. Both of the 190's in the yard had the later model actuator. I tested each one with my vacuum hand pump before extracting, and both of them were non functional on at least one of the sides.

So now the fun starts to try and find a good one. I Tok mine apart as well, and I can se the brown rubber diaphragm, but it looks to be a molded part, so not sure a stretched rubber inner-tube or something like that would work. Might give it a try just to see.. Otherwise, the search continues.

Thanks again to all!
~Bryan
 

·
Registered
Joined
·
1,382 Posts
Hmmn... If I'm going to have to do a custom fix, I wonder if I could adapt this dual-action element from a W202 for the task?

https://www.ebay.com/itm/352094018625

~B
That's definitely worth a shot since the originals are no longer available. Might have to get create w/ the mounting, but I could see it possibly working since all vacuum actuators do the same thing.
 

·
W201 Moderator
Joined
·
2,164 Posts
Thanks to everyone! I was able to hit Hayward Pick-N-Pull a week ago Saturday. Both of the 190's in the yard had the later model actuator. I tested each one with my vacuum hand pump before extracting, and both of them were non functional on at least one of the sides.

So now the fun starts to try and find a good one. I Tok mine apart as well, and I can se the brown rubber diaphragm, but it looks to be a molded part, so not sure a stretched rubber inner-tube or something like that would work. Might give it a try just to see.. Otherwise, the search continues.

Thanks again to all!
~Bryan
That sportline in there had better days, that's for sure. When I took the dash of a well kept car from Hayward P&P I took most of its actuators as I needed the same dual action one you are looking for now. It still works in my car after a year and a half. So sometimes one gets lucky, but not often these days....
 

·
Registered
Joined
·
56 Posts
Discussion Starter #11
@dolucasi - indeed the sportline was rough! I drove from south san jose to the Hayward P&P this morning, as they reported a '92 190e added on 7/29. Fresh meat, i thought.
I should have known when the photo they showed had post refresh W124 wheels on it.. Sure enough, they mis classified the car, it was the green sportline. Arrgh..

Ah well, I may give the W202 valve a try. Also looks like there's a way to use a vacuum element from the heater water control valve as a single action actuator.

Thanks again,
~Bryan
 
1 - 13 of 13 Posts
About this Discussion
12 Replies
6 Participants
dolucasi
Mercedes-Benz Forum
BenzWorld.org forum is one of the largest Mercedes-Benz owner websites offering the most comprehensive collection of Mercedes-Benz information anywhere in the world. The site includes MB Forums, News, Galleries, Publications, Classifieds, Events and much more!
Full Forum Listing
Top