Hey all. Sort of new to working on Mercedes cars, I work on sprinter vans often. Customer asked me to work on his pristine 2001 CLK 320 with a soft top.
Soft top doesn't open or close. It's currently closed. Also, rear seat head rests won't go up or down, they are in the up position.
History for context: came in a few weeks ago for soft top not working. I look into it, check wiring, check pump etc seems good. I use Mitchell ProDemand for diagnosis at my shop, but I have some sketchy wiring diagrams and pinouts that don't match up to what I have here. Anyways, I found no fluid in the pump. - - Found the hydro leak coming from the rear bow lock cylinder. I replaced it with an OEM Mercedes bow lock cylinder, no leaks now. Filled the fluid up in hopes that this was the issue with the top not working. No avail. NOW, when I activate the switch for the rear seat head rests, they work since there is fluid in the pump. The head rests will physically max out top or bottom, but if I keep holding the head rest switch up or down, the pump doesn't shut off until I let off the switch in either direction. Is this normal? Or is there some sort of limit switch this is supposed to hit and stop the pump? IF it does have a limit switch for either direction, will this affect soft top open and closing?
- Pump works for the head rests so I know the relay and the pump are good. I've also manually powered the pump, it functions properly.
- When I unlock the soft top in the front by twisting the handle and pushing it up, the switch lights up showing it's ready, that's good. When I pull it back to activate it, the switch blinks slowly. I suppose this indicates a failure. I can hear the relay for the pump click on for a millisecond and turn right off after I do this. I can hear the solenoid open and close for a fraction of a second too, seems there is an issue with a limit switch somewhere?
- I scanned the vehicle (had to use the 38 pin connector) with my TopDon scanner. I have code B1650 - Supply voltage of the soft top limit switches is faulty. Seems pretty generic.
- I took the plug of the rear bow lock cylinder, shows power and ground on connector. I reconnect, test for power and ground, now I have ground on both sides (lock closed). Is this normal? Is it supposed to ground out the power? Or is it supposed to transfer power through to the other side?
- I took the plug off of the soft top switch behind left rear seat (it's bidirectional), manually tested in my hand. Has power on both sides, If I activate the switch in either direction, it removes power, seems like it should do this. Is this normal?
- I took the plug off of the hard top cover lock thing behind the metal panel behind the middle of the rear seats. Like the bow lock cylinder, if I disconnect, power and ground. If I connect it, it grounds both sides (locked). Normal?
- I noticed the right rear little window does not fully go down. The left rear fully goes all of the way below the trim, the right rear sticks just past the trim about 1/4". Is this an issue as well?
- Does anyone have an ACTUAL wiring diagram for this unit with the control unit pin outs? I can diag a lot just from the back of the control unit while connected if i have a proper wiring diagram.
- Does anyone have a diagram of the proper switch names & numbers and locations? I've only found one for the W209.
- I've searched the forum extensively, only gaining some information here and there.

Any help you guys could provide would be massive.
Thanks,
- Doug

 

Make sure you have the truck cover roll in place, or actuate the microswitch on the right rear side. Without that, the top will not retract.

And double check to be sure the pump relief valve is tight.

 

- Pump relief valve is tight, and I have the cargo switch activated

 

These diagrams and operational protocol helped me tremendously to understand the soft top.

Which stage do you think is causing the issue?

 

Thank you for that illustration. Do you have one for the top being closed? It wont open. I'm not sure which stage of opening but I can describe what happens. With top closed, ignition on, park brake on, trunk closed, and rear head rests lowered to max, I unlock the top by twisting the handle and pushing up. All windows roll down except the right rear window does not completely go down, it sticks up maybe just 1/4 above the trim, not sure if that matters. The top switch is now lit up red. I pull back on the switch to open the top and it has a slow flash and nothing happens. I hear the relay click for half of a second and turn off. Hydraulic pump not turning on. See my original post for code and more info.

 

I don’t have the “opening” document, but I’m sure it’s out there.

I’d recommend releasing the pump pressure and using a hex wrench to release the latch then pushing the top down to the fully retracted position and then lock the cover in place. Then close the pump pressure relief and disconnect the battery for an hour to attempt to reset any codes that are in the Soft Top Computer.

Reconnect and let me know if the top will close and/or open fully.

 

I did this already, no go, still have same issue.

 

Check this thread: https://mbworld.org/forums/clk-class...p-problem.html


and I found the opening stages: