hard/soft top troubleshooting question 91SL

[aguffin]

Ok all, I have been scanning through the posts about the soft top controller on my in-law's 91 SL300 and have tried a few of the suggestions to no avail, now I need a little help!

Problem: Soft top light stays lit and blinks and chimes when vehicle moves.

I have read and reset all the codes, I originally had a 6, 7, and a 18, but am now down to 20. The hard top is installed and SEEMS to be locked. The left rear lock (done manually) does not "click" like the right does. I even tried the reset codes, drive for 10 secs and reset codes routine. Code remains at 20 like all is well and light blinks and chimes when moving.

Pressing the soft top switch either way does nothing.

The roll bar switch does nothing, even when depressed for longer than 10 secs, I do hear a relay clicking when switch is made. Roll bar is currently up.

Should I remove the hard top and try and cycle the soft top? Owner reported the soft top was getting slower and slower so they left it in the down position for a few months while it was stored. I would hate to get soft top half way up and have it remain there....

I have read the posts about the issues following a dead battery, this car sat for a few months and the battery had as much power as my 10 year old B&D rechargable screwdriver....

Any pointing me in the right direction would be greatly appreciated, it's my Sister in law's car and they think I can fix anything, do not want to spoil the illusion...

[speace]

While there are other here more qualified to answer your plea, I will share my thoughts...

The chime when you move the car is indicating it "thinks" the top is not secured.
You should be able to properly attach the top manually by securing the 4 latches.

That being said, you are probably onto something when you noticed that the left rear latch does not "click." I believe each latch has a micro switch to sense that it ie properly latched. In fact, I have heard accounts of improperly working sensors that activte the chime intermittently when the body flexes as one turns into a driveway, etc.

Food for thought!

[aguffin]

I was leaning toward that idea myself, and I did see the 4 wire harness that comes off the left rear latch/actuator assy. As a last resort I was hoping someone out there could tell me which wires I could connect to bypass the issue.

[tecqboy]

I would manually release the hard top and remove it. Instructions in the owners manual and special tool in the car's tool kit. You're going to have to trouble shoot the system and it will be much easier with the hard top removed. You are on the right path if you notice that one release does not "click". The engine must be running to provide enough electrical power to operate the system. Check the fluid resevior. Often, just excercising a micro switch will fix it. There are a pair of roll over sensors on the rear axle. If they have been activated by a sharp bump or turn into a driveway, they can affect the system operation. ( Mine were activated when they put the car on a hoist to change a tire. ) I'd read / clear the codes for the roll bar. You need to build the special switch / LED tool as discribed. You probably have this info if you did the other forum research. The roll bar and top controller interact.

[bobterry99]

For the roll bar problem I would make sure the hydraulic fluid level in the reservoir under the spare tire is sufficient and read roll bar codes like tecqboy wrote. For this you don't need to connect an LED or anything to see the codes because the roll bar MIL in the cluster is wired in parallel to the diagnostic socket. So you can just short socket #7 for 2 to 4 seconds and count the flashes of the lamp in the cluster.

For the light problem I agree that the controller is not receiving confirmation from a limit switch that the top is completely latched in place. I believe that if you re-lock the top and continue to hold the control switch until it flashes then a fault code may get stored that will identify the problem latch/switch. You may need to hold the switch for as long as about 1 minute. If that fails, then I would suggest using a basic electronic multimeter to check all of the limit switch signals to the soft top controller. If your reach this point and need help, then reply back and I or someone can give you further assistance.

[aguffin]

Thanks, I did get the roll bar codes and got a 2,3,4,5,6 (several of those) and 7 cleared them all and still no luck. The reservoir was almost empty, (refilled) and when I click the roll bar switch all I hear is a relay clicking. I'm not sure since I'm working alone if it is the bright pink relay next to the reservoir motor but it sounds like it is coming from that area. I do not hear the motor run.

After getting the hard top off the soft top code was still 20 ?? but no luck when cycling softtop switch, nothing. The only time I get a noise out of what I think is the top motor is when I use the key switch in the trunk lid. I heard that before I refilled the reservoir (is that the same for the top?) and ended up having to put hard top back on as it is pollen season here and the black interior was starting to look yellow.

After hard top is on light is off and no chime so I must have held my mouth just right installing top. It's done that before and hit a bump and the chiming and blinking starts again. I believe that I need to remove hard top again and troubleshoot soft top now that there is fluid (if there is not another hidden reservoir). I am making the assumption that the top is hydraulic also and that it uses the same fluid. Thanks for all the help and suggestions!

[aguffin]

OK, was scanning other posts and realized the noise I heard was from the vacuum (or air) pump, not the top motor. My bad, this is my first experience with a MB. My expertise is electronics, Jeeps and outboard motors.

[tecqboy]

Have you checked fuses 3, 4 and 7 in the trunk? The hydraulic pump should run for both manual roll bar deployment ( switch ) and soft top switch.

[aguffin]

Thanks, will check them out in the morning, the cover is missing from the fuse block so I did not know which drove what. I did check all of them today but I'm suspecting they might have issues when a load is applied.

[aguffin]

OK, roll bar now works, it seems fuse 7 (The large one) had a loose screw on one end. It checked out ok but when the load was applied the volts went to nothing. Top switch still does nothing but at least the pump is not toast. I do not even hear a relay click when the top switch is moved, does anyone have a diagram or at least some test points I can check? Thanks again for everyone's help...

[speace]

Originally Posted by aguffin

Top switch still does nothing but at least the pump is not toast. I do not even hear a relay click when the top switch is moved, does anyone have a diagram or at least some test points I can check?

There is likely a code in the soft top controller that may point the way.

Try this thread. AD provided some great documentation.
I 'sorted' through it and pointed out what is relative for our 90-92 SL 129 chassis.

What codes can be pulled on a 1991/92 129 500SL?

[aguffin]

Well today I manually opened and secured soft top and light in switch goes off when the last latch is locked, however the switch still does nothing. The code blinks 1 with soft top and 20 with hard top like all is well. I even tried holding the switch for about 2 minutes to see if the light would flash but nothing happened. My next step is to troubleshoot the switch but for the life of me I cannot find how to remove the center console cover, I unsnap it from the bottom end and remove the 3 screws under the change box and something is still holding it in. This has an aftermarket radio so I'm not sure if any screws are lurking around there or the climate control. I need to get that off to verify the switch works unless there is a relay somewhere else I can check. Does anyone have a wiring diagram?

Thanks!

[tecqboy]

I have loaded a video here...

http://www.sendspace.com/file/hjgysx

which will show how to get at the switches.

Tod

[aguffin]

Wow! that was great! thanks Tecqboy!
Switch does work, now I guess there's a relay somewhere? Stupid me I checked the switch with a meter but did not check power coming into plug.

Art

[tecqboy]

In case you don't know..... the controller is located under the right rear storage compartment ( back seat ). It's under a plastic cover. If I remember correctly, there are two relays on one end. I believe they are for the left and right power window motors. The windows must operate in sync with the top. The windows should go down as soon as the "top" switch is activated. In believe that at some time in the past Bob Terry posted some of the pin outs for the top controller. I checked my "stuff", but I don't have them.