SL/R129: soft top switch not lighting up
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mercedes 129
soft top switch not lighting up
Hi Everyone,1991 sl 320 The car was sitting for a while and after putting new battery on the soft top does not show any signs of working.Have checked the fuses -the big 30 amp blade fusewas gone -replaced it to no avail.the roll bar functions up and down from switch.try the red button for soft top and absolutely nothing happens,it does not light up,the windows do not move(they work fine with the switches) tried putting windows down with the individual switches ,still nothing.tried pulling the codes ,the switch lights up but does not blink any codes.on pushing switch forward it does move the roof slightly ,could it be the module as I cannot even read the codes?
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From: Atlanta, unfortunately
'09 S600, (2) R129 300SLs, '03 SL500, '03 SL55
I presume you are shorting diagnostic socket #10 of the 16-socket connector to chassis ground for 2-4 seconds. If so, then I would check the state of the limit switch inputs to the roof controller. If you have a multimeter for testing and wish to do that reply back for needed help.
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From: Atlanta, unfortunately
'09 S600, (2) R129 300SLs, '03 SL500, '03 SL55
The following procedure is for cars built in calendar year 1993 or earlier. You'll need a basic electronic multimeter or other device for checking electrical continuity.
All the switches are wired between chassis ground and individual sockets of the top controller's "Y" connector -- the largest of its three connectors. Access the top controller behind the right seat and disconnect Y. Observe that there are sockets arranged in two rows that are numbered sequentially (attachment).
You proceed by putting the top in "Position 1" and checking the open/closed state of 15 switches and then repeating the same for "Position 2". With the ignition off you check a state by measuring resistance between a switch's socket and chassis ground. Infinite resistance indicates a switch is open, resistance less than 1 ohm indicates a switch is closed. The information below describes the two positions, the 15 sockets to check, and what state to expect with each measurement.
Position 1 (Top closed, roll bar up)
Open: 27, 29, 30, 31
Closed: 16, 17, 18, 19, 20, 21, 23, 24, 25, 26, 28
Position 2 (Top open and stored in compartment with storage compartment cover open, roll bar down)
Open: 16, 17, 18, 19, 20, 21, 23, 24, 25, 26, 28
Closed: 27, 29, 30, 31
All the switches are wired between chassis ground and individual sockets of the top controller's "Y" connector -- the largest of its three connectors. Access the top controller behind the right seat and disconnect Y. Observe that there are sockets arranged in two rows that are numbered sequentially (attachment).
You proceed by putting the top in "Position 1" and checking the open/closed state of 15 switches and then repeating the same for "Position 2". With the ignition off you check a state by measuring resistance between a switch's socket and chassis ground. Infinite resistance indicates a switch is open, resistance less than 1 ohm indicates a switch is closed. The information below describes the two positions, the 15 sockets to check, and what state to expect with each measurement.
Position 1 (Top closed, roll bar up)
Open: 27, 29, 30, 31
Closed: 16, 17, 18, 19, 20, 21, 23, 24, 25, 26, 28
Position 2 (Top open and stored in compartment with storage compartment cover open, roll bar down)
Open: 16, 17, 18, 19, 20, 21, 23, 24, 25, 26, 28
Closed: 27, 29, 30, 31
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mercedes 129
Hi again, thanks for that -did the dheck and all checks out ok as the list of open and closed using multi meter for continuity ,but roof still not working -however after I have closed the roof manually if I press the button to close the roof it tries to pull the top further down as if it is not sensing that it is latched
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From: Atlanta, unfortunately
'09 S600, (2) R129 300SLs, '03 SL500, '03 SL55
When the pump is running all 6 lock cylinders are pressurized, and unless the sequence calls for a lock to open or be open, it will be pressurized to close.
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mercedes 129
I have checked the windows and the rh window is showing a 20 ohm resistance to earth with the window down I am going to check the earth point on the crossmember under the seat.What I mean about pressing the button to close ,once I have manually closed the soft top,and it attempts to pull the front down into the locks further rather than continuing with the cycle to raise the windows
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From: Atlanta, unfortunately
'09 S600, (2) R129 300SLs, '03 SL500, '03 SL55
This is consistent with normal operation. The top switch will only raise the windows if actuated within 2 seconds of completing the sequence of automatically closing the top.
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Thread Starter
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mercedes 129
I have cleaned the earth point under the passenger seat (rh it is lh drive) and it gives 8 ohm resistance now,but if I disconnect the battery there is 0.05 ohms resistance.Also at one point I could hear the hydraulic pump cutting in and out without touching any switch-any thoughts? I am thinking now more that the module is at fault?
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From: Atlanta, unfortunately
'09 S600, (2) R129 300SLs, '03 SL500, '03 SL55
I suppose by far the most likely cause of this is a faulty roof controller turning-on the pump. If you were to disconnect the controller's Y connector and find the pump ran, then this would eliminate the possibility that the roof or roll bar control switches were the problem. If then you removed the module and the pump ceased to turn-on, then this would prove to my satisfaction that the controller is faulty.
