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170 roof not going down, red switch no lamp

3K views 27 replies 6 participants last post by  Dave2302 
#1 ·
Hello friends,

slk 230 roof decided to not go down. Red roof switch is not lighting up in opening mode, no sounds from the roof at all, except when switch is in closing phase, than the light illuminates the switch and i can hear pump working. Hydraulics are fine, no leaks, fluid is at fill level, micro switch on the curtain on the trunk right side is working so is the roof relay located at the pump.

Has anybody experienced this issue.

Thank you.
 
#6 ·
Hello,

I replaced the Vario roof switch thinking that the vario switch was the cause of roof stuck closed it did not fix the problem, switch flashes upon ignition for a few seconds, light and pump is running when pressing button to close roof, but when I pull switch back roof will not open, no sound, no light nothing, if I ground pin 28 to ccm/mfcu roof opens, and I can close it normally with the Vario switch, all switches test ok with voltmeter i get a 00.0 ground read all but switches s69/11 and s69/12 they read 12.65v, trunk light works, I checked s69/12 tumbler and latch micro switch they are clicking...

Hopefully someone may have had the same problem and may give me some insights.

Thank guys.

::alido pavan
 
#8 ·
I bought an SLK230 last week. When I first went to see it the same thing happened. He called me back less than an hour later. The problem was, he said, that the cover in the boot (or trunk as you would probably call it) was not pulled back. Once it was pulled back the roof worked fine.
 
#10 ·
BTW - here is some additional information to test your old switch. Technically, your switch is a "single pole, double throw momentary contact with center-off". Translated, the switch has a common pole, pin 4, which should be connected to either pin 5 or pin 7 if you push or pull on the switch (i.e. 0 ohms resistance). If you release the switch, pin 4 should not not connected to either (infinite or OL resistance).



In situ, pin 4 should be connected to ground, pin 5 and 7 should be connected to the MFCU pins 28 and 29, respectively.



Pins 1 and 2 are for the bulb inside the switch; I'm not sure what pin 3 does (it is connected to the interior wiring).
 
#12 ·
efair,
Sorry to enlist your help again, I did not test the old switch but
I tested the new one, and switch is fine, as I mention early if I ground
pin 28 roof opens, I can close the roof with the vario switch, or by ground pin 29,
I looked at the wires under the console and they look okay, is there a way to trace them
to them n10-3. Am I thinking correctly to assume that if the roof opens
by ground pin 28 that the problem is with the switch and or wiring
leading to the n10-3 and not with the various microswitches.

Thanks,
 
#13 ·
Hi,

So what happens if you ground the "switch end" of the pin 28 wire ?

If it doesn't work, bad wire / connector between the 2 parts

If it does work, bad switch

HTH, cheers Dave
 
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#19 ·
Hello,

and thank you for your response,
I finally got the time to check the switch and wire situation,
switch tests ok, wire is not ok, when i ground wire anywhere from switch to pin 28 roof will not open,
but when I ground pin 28 at the N10-3 roof opens perfectly (and closes when activating the red switch)

Wire from switch leading to pin 28 looks ok, I checked the wiring harness connecting to the switch and it looks fine too.....all wires on pigtail look fine....

Thank again for your feedback.

::alido pavan
 
#21 ·
Hello,

I ground the wire with a digital test insulation-piercing probe by piercing into the wire sheeting and probing at the harness points at the switch and connect the clamp end of the test light to the chassis, as mentioned earlier when I ground pin 28 grey/violet to chassis via paper clip inserted at the MFCU location roof opens perfectly.

I was thinking of running a wire starting from the vario switch base and connect other end via paper clip to pin 28 at MFCU, and see if the roof will open via switch.

I just want to say again thank you for you great help and time you are taking to solve this roof challenge.
 
#23 ·
efair,

wow, I connected a wire from the red switch pin grey/violet wire to the mfcu pin 28 and the roof opened, light on red switch lit, and it closed perfectly. Good news, the wire is the issue, when i probe wire at the mfcu pin and away from the pin leading up to the fire wall wire is alive i can ground wire roof opens, test light lights up, somewhere from the fire wall to the red switch wire is dead, i tested the violet/grey wire at the red switch and up to the shift console and wire is dead, cannot ground test light does not light up. i need to bypass grey/violet wire. not sure how i can feed a new wire from switch to the mfcu, do i need to open up the center console to feed wire to mfcu, is there a less involved path?

Thank you,

;;a
 
#25 ·
Hi,

very hard to see under the fusebox on 2001 slk 230, and locate grommet on firewall, does the fusebox unit need to be disassembled.... i tried to track pin 28 grey/violet wire from the inside of the car, passenger firewall under the carpet thinking i could bridge wire to switch from there if wire was good but i could not locate it. I also removed battery to see if there was a grommet leading to inside of cabin, no luck.....

Thank you in advance for advice.
 
#27 ·
Hello,

I want to thank you for all your help on solving my roof not opening issue.
I rewired wire from pin 28 to switch through the firewall
into the cabin and to the switch and i bypassed old wire and it works!

I have a final question. I by passed the old wire connection and replaced it
with a new wire, I did not spliced the new wire to the old wire, i hope the was the correct
move, is that okay.

Again a big thank you.
 
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