SL500 R129 Roof issue

[Mark Perry]

Hi
A little help if possible, my SL500 1992 has an annoying fault, it keeps sounding the roof not fitted correct alarm when the roof is locked and fine, it does this with the hardtop and soft top, and it only makes the noise when you use the brakes, ive checked and oiled the micro switches above the windscreen but no joy, still does it.
ive disconnected the battery and left for 30 mins to see if that cleared it but no.

Any advice welcome

 

[MarkyC71]

Did you get anywhere with this. I have just had my roof replaced and even though it is latched properly the alarm keeps going off. If I keep button pressed forward it tries to latch and then stops sounding but as soon as I release it come back on.
Any advise would be helpful or someone in Leeds area that knows what they are doing with these roofs.

 

[RichardF]

Did you get anywhere with this. I have just had my roof replaced and even though it is latched properly the alarm keeps going off. If I keep button pressed forward it tries to latch and then stops sounding but as soon as I release it come back on.
Any advise would be helpful or someone in Leeds area that knows what they are doing with these roofs.

It's not unusual. When a new tops been fitted the tension keeps the front micro switches from registering it's closed.

I followed these instructions it'll only need a tweak. To see which switch needs adjusting use your manual locking tool on each side in turn to pull it down and stop the alarm.

Fix: New soft top or new front gaskets resulting in soft top not closing in the rear - Mercedes-Benz Forum

 

[Mark Perry]

Im going mad

Help please im going round in circles, i still have the same fault where the roof switch flashes red only when the brakes or indicators are used whilst moving.
When i stop it goes silent.
This happens only when the soft top is up, when down no problem.
When parked with roof up its fine if i push the brake pedel whilst parked the light goes red but no noise, when i drive no noise no flash, hit the brakes or indicators and flashing and beeping.

Ive checked all the pistons (found 1 rear was slightly leaking and have replaced it).
Have adjusted the front micro switches
Have reset all the fault codes
have syphoned out the old fluid and replaced with new MB fluid for good measure.

But its still flashing, it alters flashing when im braking and indicating to the point its effecting the idle by it falling and rising.

Some pointers please before i just go back to driving it roof down all the time with a coat and hat.:fail

 

[dinoy]

where r u based my local merc guy did reset/adjustment on mine and worked fine , he is based in wembley london though

 

[rockits]

It's not unusual. When a new tops been fitted the tension keeps the front micro switches from registering it's closed.

I followed these instructions it'll only need a tweak. To see which switch needs adjusting use your manual locking tool on each side in turn to pull it down and stop the alarm.

Fix: New soft top or new front gaskets resulting in soft top not closing in the rear - Mercedes-Benz Forum

Thanks. I will take a look at this one. I have a similar issue after popping the hardtop on. It seems to be all on OK and sat down nicely. Just the alarm goes off for 10 secs on pulling away then stops and is OK. It all seems sat down front and back so likely some sensor issue or similar.

 

[RichardF]

Help please im going round in circles, i still have the same fault where the roof switch flashes red only when the brakes or indicators are used whilst moving.
When i stop it goes silent.
This happens only when the soft top is up, when down no problem.
When parked with roof up its fine if i push the brake pedel whilst parked the light goes red but no noise, when i drive no noise no flash, hit the brakes or indicators and flashing and beeping.

Ive checked all the pistons (found 1 rear was slightly leaking and have replaced it).
Have adjusted the front micro switches
Have reset all the fault codes
have syphoned out the old fluid and replaced with new MB fluid for good measure.

But its still flashing, it alters flashing when im braking and indicating to the point its effecting the idle by it falling and rising.

Some pointers please before i just go back to driving it roof down all the time with a coat and hat.:fail

It's an odd one for sure. Have you tried cleaning, checking, replacing fuses? They can cause all sorts of bizarre electrical problems. What year is your car? Have you tried reading the codes?

 

[Mark Perry]

Hi
Thanks for reply, the codes listed as 16 to 19 which are about the windows and 29, i can get the number description and will post shortly, the car is a 1992 500sl, im going to check all the fuses today as the way the electrics acted it had me thinking it was some sort of short, once i cleared the codes and took it for a drive it showing no errors at the moment.

Mark
From Bolton

 

[Mark Perry]

Right had some more time to spend on the car and still having the same problem.

I've gone through all the roof lock switches (all four) and have adjusted them,
Have gone through all the fuses and cleaned/replaced any dodgy ones (both boot and front fuse boxes).

The problem is still there and im thinking it may be a bad earth as its only beeping when i hit the brakes or use the indicator.
Its also rising and falling with the beat of the indicators

Can anyone provide a diagram of the earth points? or maybe a full wiring diagram so i can find a common point?

Thanks

 

[Mark Perry]

Also connected the code flasher and its showing no errors on the soft top

 

[Mark Perry]

Fixed it, i returned back to the fuses, they looked ok but replaced them and bingo it runs like a dream without any strange electrical gremlins.

Oh happy Days

 

[Mark Perry]

Scratch that its back again, help please....
Could it be the roof switch or a common earth connected with the brake and indicators?


Help

 

[RichardF]

Maybe check the battery. AIUI as they get older internal restistance increases, car cranks and starts ok but it causes electrical gremlins.

I'm not an electrical expert but just trying to think logically. The idle is affected by the indicators and flashing. Would this indicate a large current draw? Would it be worth checking the voltage drop while this is going on?

Have you tried fiddling with the fuses again?

 

[RichardF]

I'm not sure about shared earth points but one under the rear seat by the roof control module and one in the boot underneath the fuel filler. Both these seem quite major with plenty of earths going to them from the roof controller.

On the wiring diagram theres a 12 pole connector (X18) It shares rear tail light harness, soft-top controler functions, door switchs, backrest locks amongst other things. According to my info it's the left hand footwell behind the cover, but my info also shows a LHD car, sometimes the positions are reversed.

Something else thats just occured to me. To narrow it down maybe try it with the tail light(s) disconected. Do the hazard lights have a similar effect

 

[RichardF]

I've found a common earth

Left hand side of the boot behind the cover, soft top switch (bow) left and right, roll bar switch and (drum roll) rear light clusters.

Lets hope that's it.

 

[Mark Perry]

Love you guys, thanks for more direction, will have a play when Im home from work and let you know.

Thanks again

 

[Mark Perry]

Richard your a star got back home early, pulled the boot liner back and one earth wire/strap in need of a good tighten, Went for a drive up Rivington through the twisty roads and all seems fine now no beeping.

will keep my fingers crossed thats the last of the niggles:bannana:

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