wardhill

. My 2003 sl keeps blowing the soft close fuse #56 I think 20 amp. I recently repaired the leaking ports on the trunk lid latch. Everything work for a day now I can hear the pump but when it nears the end of its cycle it blows the fuse. This blown fuse prevents the top from operating and doors from locking . Any thoughts? Thanks

matk

Sounds like a problem with the PSE pump in the boot. Either the pump is faulty or there is another leak in the air circuit causing the pump to overrun. Do you have anything to get codes from the car? Where are you located?

wardhill

I live in southern Maine . I did notice moisture on the hydrolic pump but the pse pump is below that. Correct?

bobterry99

Yes.

The pump motor is drawing too much current surely due to a faulty impeller. Someone on this forum or Benz World described a reasonably-priced repair kit a few weeks ago. Another member stated they had no interest in restoring pneumatic operation but wanted their roof working. In that case removing the impeller would be a solution.

wardhill

Ive removed the pose pump and took it out of its housing . Seeing a fix on the pressure switch about the copper tabs touching. Mine were touching under the adjustment wheel only. Should they be ? the others we’re not touching. Ive attached a picture so it’s the copper tabs to the right in the picture under the adjustment wheel that were touching each other I have since pushed them apart

DavidCA

The two tabs on the right in your photo SHOULD be touching, that is not your problem.
The tabs are pushed against each other by the white plastic disc (disk) If you have moved the tabs, you can unscrew this disc (after taking note of the position) then straighten the tabs and screw the disc back in.
Your problem is with the motor / pump unit.

matk

Unsolder the motor connections and look at at the other end of the motor. You can remove some screws and the end cap can be removed to access the impeller. If you get some graphite dust coming out as you loosen the end cap that’s a big clue that the impeller has broken.

If the impeller has gone they are obtainable on eBay. Please note there is a specific way to reassemble, you can’t just bolt it up again. You need to check he pressure it’s delivering by hooking up to a 12V supply and measuring pressure and adjusting the end screws. See here

wardhill

Thank you I’ll look at this today and let you know I appreciate your help on this

wardhill

Question, if you buy a whole pump assembly ,entire black box, do you need to program it to your car?
thanks

DavidCA

If you buy used, who knows what coding you will get, if you buy new the MKL (pressure for the seats) is turned off by default.
So you will need a Mercedes Star system to check and change the coding.
I re-con the units and sell on ebay (UK), attached is the coding that I set for my PSEs.

wardhill

Ok I disassembled my pump and the impeller was completely intact. I did notice some carbon dust on one side of the ports and wonder if a channel is clogg causing the fuse toblow

matk

Are all the vanes that sit in the impeller grooves intact?

DavidCA

I believe you will find that the motor is faulty.

matk

Well that should be easy to test, just stick 12volts on it.

wardhill

I did this and it runs fine I’ll do the pressure test tomorrow thanks

wardhill

Cleaned the air ports and electrical connection reassemble and all seems to be working fine. I think my problem was debis from the impeller had clogged the supply port

matk

I’d be tempted to consider change the impeller while I was in there. If you have enough debris off it to clog a port that would be a bit concerning

wardhill

good point