more r129 roof problems

[graham58]

Hi after not using my sl for a while i now have a problem with my hard top.The red roof light switch is on all the time,if i pull it back i can hear the pump running and it starts to flash but nothing else happens.If i push it forward the rear of the hard top pulls down at the rear,then when i release the switch is still red.Could anyone point me in the right direction thanks.1992 500sl.

 

[DSB SL AMG]

Sounds like a classic you have not activated the foot handbrake...the hardtop operation will not work unless handbrake in ON. (I know because I have done it a few times after winter storage)

Try this first...

Hi after not using my sl for a while i now have a problem with my hard top.The red roof light switch is on all the time,if i pull it back i can hear the pump running and it starts to flash but nothing else happens.If i push it forward the rear of the hard top pulls down at the rear,then when i release the switch is still red.Could anyone point me in the right direction thanks.1992 500sl.

 

[graham58]

Sounds like a classic you have not activated the foot handbrake...the hardtop operation will not work unless handbrake in ON. (I know because I have done it a few times after winter storage)

Try this first...

thanks yes you are right it had been parked with the handbrake off.but i have since put the handbrake on.On closer inspection the buzzing sound is not coming from the pump but from the inside of the boot on the right where there is some electrical connections.I have removed the hard top manually,but the soft top will not work either.I have cleaned the fuse in the boot for the roof operation and cleaned the connections to the pump but still nothing.

 

[DSB SL AMG]

The R129 rood system is really sensitive to battery charge, is the battery fully charged? are you operating the button with the car running? it could also be the roof fuse (look in hand book), not sure which one but its in the boot rhs fuse box?, might be worth removing, cleaning, then putting back...

Also if the battery has been disconnected have you reset the windows and roll bar?

thanks yes you are right it had been parked with the handbrake off.but i have since put the handbrake on.On closer inspection the buzzing sound is not coming from the pump but from the inside of the boot on the right where there is some electrical connections.I have removed the hard top manually,but the soft top will not work either.I have cleaned the fuse in the boot for the roof operation and cleaned the connections to the pump but still nothing.

 

[graham58]

The R129 rood system is really sensitive to battery charge, is the battery fully charged? are you operating the button with the car running? it could also be the roof fuse (look in hand book), not sure which one but its in the boot rhs fuse box?, might be worth removing, cleaning, then putting back...

Also if the battery has been disconnected have you reset the windows and roll bar?

Hi again DSB yes its a brand new battery and been trying to operate the roof with the engine running,cleaned the fuses in the boot and reset the windows and roll bar,they are all working fine.Iknow it runs through a series of operations ,the first being the windows go down ,but they are not going down so nothing else would work.i,m stumped.thanks.

 

[star]

Have you jumped started it? As the roof control units are prone to failing if jump started.

 

[Parisien]

Piggy backing on Grahams thread, my roof only part opened when I tried it, ie the rear compartment opened ready to receive hood but it would release the front latchs, thoughts?


P

 

[DSB SL AMG]

There can be many, many causes of R129 roof operation issues...please try the above areas first.

Piggy backing on Grahams thread, my roof only part opened when I tried it, ie the rear compartment opened ready to receive hood but it would release the front latchs, thoughts?


P

 

[DSB SL AMG]

+1 jump starting can fry the R/module...

Have you jumped started it? As the roof control units are prone to failing if jump started.

 

[graham58]

Have you jumped started it? As the roof control units are prone to failing if jump started.

yes once last week to move it,if thats the case what next ? help,,

 

[television]

Looking like it needs a new control.... always disconnect the battery for a reset, you must re set the windows after this and try it.

 

[DSB SL AMG]

Unfortunately as already stated you could have 'fried' the module, they are sensitive to power spikes...I would still double check the fuses and relays...and manually cycle the roof a few times, worth checking micro switch positions as well.

The only real roof module test check is to get the part no, from memory the unit is located RHD right drivers seat in the storage compartment under a black plastic cover, try and get another unit to swap over and test , OR send the unit away to be tested. I think the part no for 1992 car would be •A129 820 00 97 : MY 1990 - 12/93, which you need to check.

Note at this time of year used/spare/ refurb modules are like rocking horse pooh to find, new from MB circa £1k.

Known Test / Repair Company's

https://autotekelectronics.com/roof-hood-control-unit-pump/1992/mercedes/300sl/?page=1
http://www.mbcluster.com/Services_ECU_Mercedes.htm
http://www.bba-reman.com/gb/content/mercedes_slk_roof_control_module

Spares
Carl http://www.w140.co.uk/

Seems to be a lot of forum owners with faulty R129 roofs at the mo

yes once last week to move it,if thats the case what next ? help,,

 

[Parisien]

Ok, mine hasn't been jump started, battery fully charged


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[star]

Piggy backing on Grahams thread, my roof only part opened when I tried it, ie the rear compartment opened ready to receive hood but it would release the front latchs, thoughts?


P

As your roof starts to move, different problem. Unlikely to be control unit. Get the position of the micro switches read, one could have failed.

 

[Parisien]

Ok, thanks for that

P

 

[television]

Do try a battery disconnect, its free. Do the windows work ok on their own.

 

[graham58]

well thanks for all the replies,seems like i have the wrong cars,my every day to day car is a range rover p38 gremlin special ,says it all if you know anything about p38,s.they are both great cars and wont be parting with either,but would be nice to jump in them and just drive them.I remember years ago when i was a young guy with no money i bought a vw variant. I bought from the car auction for 300 quid ran it for 4 years ,never put a spanner on it or cost me a penny ,then sold it for the same price i paid for it.heaven lol.the battle continues.

 

[DSB SL AMG]

My car is an early R129 1992...I Had some fun and games last summer, hard top came off fine, my soft top roof opened fine, on closing it was sticking, I was pretty sure it was NOT a roof module issue...early SL R129 roof issues can be a nightmare to diagnose, as already stated pre digital diagnostics and STAR, must be remembered at the time of R129 launch (1989) the system was very advanced and state of art ....it takes lots of time and effort and part swapping at times to define issue root cause, very difficult if in a trade garage due to labour intensity, charges, running up huge £££ considering the price of pumps and modules in relation to minimal values of the cars...I followed simple early root cause investigation sequences :-

1. Ensure all windows / roll bar are reset after battery disconnect.
2. Ensure Battery is fully charged.
3. Operate soft top roof with engine running.
4. Any issues check micro switch positions.
5. Check micro switch inputs with multi meter (to establish signal from RCM).
6. Check pump reservoir.
7. Operate roof manually 3/4 times.
8. Blink box check.

In my case all the above checked out okay, even blink box results were okay, luckily the garage had a SL of my vintage and we swapped over roof modules, my roof then worked okay, we put my module in the other SL and it then exhibited the fault, root cause determined, new roof module required all now fine (thanks Carl Burgess).

I think yours is a 1996 SL? so you should be able to hook up to STAR to read roof fault codes without the need for blink box diagnostics...

Ok, mine hasn't been jump started, battery fully charged


P

 

[DSB SL AMG]

You have a P38 true money pit GOLD star award, I bet you are familiar with your local Alicante LandRover specialist...

See ^^^^ post you wil get sorted on the R129, it just can be labour intensive and you may end up needing to swap some bits over to determine cause...

PS. if you do end up requiring a roof module or bits always worth looking in for sale section / posting wanted ad, look on both forum sides...

well thanks for all the replies,seems like i have the wrong cars,my every day to day car is a range rover p38 gremlin special ,says it all if you know anything about p38,s.they are both great cars and wont be parting with either,but would be nice to jump in them and just drive them.I remember years ago when i was a young guy with no money i bought a vw variant. I bought from the car auction for 300 quid ran it for 4 years ,never put a spanner on it or cost me a penny ,then sold it for the same price i paid for it.heaven lol.the battle continues.

 

[Parisien]

4. Any issues check micro switch positions.

How can I do this, simple to do so, easy access.....diagram?

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