99 Mercedes Benz SL500. When closing the convertible top, the cover sticks just before the front latches. A slight pull on the cover fixes the problem and operation returns to normal. The soft top opens fully and without help. Why does the cover stick?

 

I would look at the open/closed status of all of the limit switch inputs to the roof controller and see if one is in an incorrect state. To do that you remove one of the controller's two electrical connectors and use a multimeter or other instrument to check continuity between various points to chassis ground. If you want to proceed with that and desire help, then reply back.

 

There is a switch on the passenger side that is moved by the covers arm. This switch is working correctly, but my thoughts are that the programming says this switch should be closed even though it's open. I have a Snapon Verus scan tool and have tried finding codes from the soft top, but I can't find them. As I said, if you move the cover just an inch, it "fixes" it for the remainder of the cycle. After it closes completely, you can open it fully and then close it until the front part of the top is touching the latches and the back part of the top is fully up with the cover fully up. It stops and requires you to manually push the cover an inch forward before finishing the closing cycle.

Is there a way to check the computer? I also have a Wells tester at my disposal.

 

A Mercedes Star Diagnosis System will can do this. A system based upon a Chinese clone can be put together for about $300.

 

Unfortunately, I don't have one and I don't have $300. I do have a Snapon Verus Pro that I can use though...

 

If that has a cable with a large, round, 38-pin connector to plug into the vehicle then I suppose it can read the state of the inputs to the controller without having to use a multimeter.

 

So, the switch I mentioned, it tells the computer that the cover is open or closed. When putting the top down (opening), the steps are in this order... Windows open, back part of the roof unlatches and moves up, cover unlatches and opens, front part of roof unlatches and the entire roof begins to fold down, with folding complete the cover now closes and latches, windows go up.

When putting the top up (closing), the steps are in this order... windows open, cover unlatches and opens up, the roof raises up and unfolds with the front touching the latches but not latching yet, the back part of the roof is still folded upward and the cover is still open. This is where it stops. The driver gets out and pulls the cover just an inch forward, then gets back in and pushes the big red switch once more and everything works fine once more. Now the front of the roof latches, the cover lowers and the back of the roof lowers and latches, then the windows close once more.

My problem is that the driver has to get out and manually pull the cover forward one inch. The entire thing should happen from the driver seat with the push of a button. Now, the switch that I mentioned earlier that tells the computer that the cover is open... that switch is doing its job correctly. If it was not attached, the process would stop at the same point also when opening the roof as it does when closing. It is sending the proper signal. I feel like the computer is interpreting that signal wrong. I just did an Ohm check on the switch. When the cover is open, the circuit is open in that switch. When the cover is closed, or even pulled forward an inch, the circuit is closed. This is where I'm confused. I do have a multimeter. If I'm testing the wrong things, please tell me so I can finish this project and regain my sanity.

Thank you all for taking the time to offer suggestions and your help.

 

The S84/4 magnetic switch wasn't reading! Now the top opens and closes without help. Thank you all for your help!