1985 300sd. I have a leak at one of my door lock switches. I have verified that trunk and fuel door is not problem. Can anyone guide me on a simple way to troubleshoot without taking all the door panels off? Comments and suggestions welcome. Thanks

Do you have a Mity Vac? a very useful tool with these vacuum systems.

I haven`t troubled shooted the 126, more familiar with the 123. but the 126 has the vacuum pump in the trunk for the lock system.

On the 123`s the vac lines run under the carpet and connected with rubber T`s. just disconnect the different lines and pump up with the mity vac to see which door is the problem child.

Do some search on the vacuum, lots of writeup on it.

You can spend a fortune taking it to a shop for them to chase down these vac problems. been there.
bought a CD off a guy on e-bay (SYMBOLGUY) that explained it for me. this was way before I discovered this site.

Charlie ☺

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there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works

If you're just trying to figure out which door is leaking, try plugging the ports in the splitter under the passenger front carpet.

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-Josh
Testing the cheap Mercedes axiom, one bolt at a time...

That was what I was looking for. I did not know where the splitters were located? Is there other locations with splitters? Thanks

Start on the engine side of the firewall and put your mity vac there and suck down the locks. If they all go down quickly, I'd check the rubber unions in the engine compartment b4 I go to the interior. Work from the lock feed engine side back to the vac trunk main/booster line. see if you can maintain vac there. Then go inside the car under drivers mat and go door by door. The other 3 door locks are all controlled off the master switch in the drivers door.

On the SD the vacuum for the door locks is supplied by a vacuum pump in the trunk, not the vacuum pump on the engine so he needs to start there.

The only splitter that I know of for sure is the one under the passenger carpet, hidden under the plastic trough just inboard of the sill.

On mine, there were three lines there, one serving the driver's rear door, the other two going to the right doors.

My front right was out, so it now has a golf tee plugging it until I work up the motivation to tear into that door to fix it. (More likely now that I can cannibalize it from a parts car!)

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-Josh
Testing the cheap Mercedes axiom, one bolt at a time...