CLK 230 (2001) Roof Electrics

[CLIFF SMITHSON]

Hi everybody,
Any help once again would be really appreciated. Does anybody know if a Star code reader can check the electric motors operation which drives the hydraulic pump to lift the roof?
Secondly can the motor be bought separately from the pump if a secondhand hand part is to be purchased?
My roof problems have been going on for nearly three months now but with a series of tests l have managed to pin the fault down to the motor driving the hydraulic pump, I Think !
Cliff.

 

[LostKiwi]

As far as I'm aware the motor is integral to the pump.

Star can monitor the state of switches and electrical signals to valves but unless there is a feedback sensor cannot tell if those signals to valves have resulted in an actuation. In practice the method is to tell the pump and valve to do something then wait for confirmation the action has completed when the switch signals it has. If it does not it will usually record the failure as a diagnostic code.

 

[Uncle Benz]

There is a yellow relay near the pump which switches the motor on and off. They are common for trouble. You can bridge the terminals in the plug to run the motor, but don’t run it for more than a second or two like this. Might be worth checking that before you condemn the pump unit. I have seen the motors fail before, but it isn’t common

 

[CLIFF SMITHSON]

Thanks Uncle Benz and Lost Kiwi for your thoughts, l have checked and also changed the relay, it’s ok and it also a black simple four pin relay which has been used for years. Often used to operate fuel pumps at the turn of the century on many vehicles I can’t believe it’s the relay terminal block that’s faulty, there again it’s worth eliminating.
On your thoughts Uncle Benz at least l know what l’m going to have to buy if motor/pump is faulty. l think my best bet is to trace the supply wire going to the motor and see if a supply is found when the roof switch is operated. Its a bugger to get to round the back of the pump/motor but l do have a wiring diagram that l think is accurate.Thanks again.
Cliff.

 

[CLIFF SMITHSON]

Hi,
I’ve just written your replies when lm realised that power supplied to the relay should energise the motor without locking got the wires entering the motor. It’s often by talking through problems that ideas and solutions come into your mind. With all due respect to my wife, she is not technically minded and can sometimes be illogical in her thought processes, mind you, this can be very useful when you need to ‘think out of the box’ at times.
Cliff.
.

 

[Uncle Benz]

I’ve been known to prise the plastic box off the relay and close the armature with a finger before to run the motor. Not best practice, but you know

 

[LostKiwi]

I’ve been known to prise the plastic box off the relay and close the armature with a finger before to run the motor. Not best practice, but you know

Ditto.

 

[alexanderfoti]

STAR can read the values of the limit switches etc, but it needs to be an older one, as it uses HHT win on the older CLK's

 

[CLIFF SMITHSON]

Hi everybody thanks for the feedback, l’ve looked at the wiring diagram this morning and the pump / motor relay would give me an access point, with the relay removed l could link across terminals 30 & 87 with two male spade terminals and a short wire. If l try this for just a second with the roof unlocked and the windows down l should hear the pump start up. This would eliminate the pump / motor out of the equation.
All l now need is my wife to return from the supermarket and she can hopefully operate the switch while I touch the two terminal together.
Cliff

 

[CLIFF SMITHSON]

Hi everybody,
Sorry for the delay in replying , l’ve really ill with food poisoning and l’m just getting back on my feet, l really had it bad, my wife’s trying really hard to get rid of me l think! Only joking.
I did manage to test the motor on the hydraulics for my roof operation and found the unit was faulty. This has since been changed, l now has rear head restraints which go up and down, and a roof which operates from the down position but needs to be lowered manually. I thinking perhaps it’s the bow lock switch which is preventing the roof from lifting from the start position. Anybody any thoughts?
Regards Cliff

 

[alexanderfoti]

Yes, a limit switch must not be engaged, must be the one in the release latch above your head though? Does the motor run at all when trying to lower?

 

[CLIFF SMITHSON]

Hi,
Thanks for your reply, in answer to your question, the pump doesn’t run when the roof is unlocked but the windows lower. It seems as though the lock which holds the rear section of the roof in place is not being released or activated.
Even just discussing the issue with other people starts the brain cells turning and it’s made me wonder if l manually released that lock from up inside the boot and then tried to operate the roof by the switch whether it would prove if that lock was faulty? Thanks again for your response.
Regards, Cliff.

 

[alexanderfoti]

Does the roof button flash quickly when the windows lower but nothing else happens?

Yes, you are right, normally moving the roof manually to the next stage can help to identify which component is giving problems.

It will be very likely a micro switch somewhere. It can be difficult to identify the issue without diagnostic equiptment though.

 

[Uncle Benz]

Does the roof button flash quickly when the windows lower but nothing else happens?

Yes, you are right, normally moving the roof manually to the next stage can help to identify which component is giving problems.

It will be very likely a micro switch somewhere. It can be difficult to identify the issue without diagnostic equiptment though.

I’ll be brutally honest mate, even with the HHT, which these early cars use, diagnosis can be hard. Experience with these is everything in my opinion.

 

[Uncle Benz]

Look through the nearside and offside rear quarter windows with a torch. On the offside, deep in the corner you should see the shiny metal rod of a hydraulic ram. On the nearside you shouldn’t see it. It should be covered by a black sliding section that operates a two position microswitch. If you can see a shiny piston ram that side too, the switch has buckled and popped off. It’s the single most common fault I’ve encountered over the years. There are others, but I must have done a hundred of these switches over the years

 

[alexanderfoti]

Look through the nearside and offside rear quarter windows with a torch. On the offside, deep in the corner you should see the shiny metal rod of a hydraulic ram. On the nearside you shouldn’t see it. It should be covered by a black sliding section that operates a two position microswitch. If you can see a shiny piston ram that side too, the switch has buckled and popped off. It’s the single most common fault I’ve encountered over the years. There are others, but I must have done a hundred of these switches over the years

+1 see lots of these broken. Rather pricey too, although I think ops fault would be somewhere else as the roof wouldn't go up with this broken?

 

[alexanderfoti]

I’ll be brutally honest mate, even with the HHT, which these early cars use, diagnosis can be hard. Experience with these is everything in my opinion.

I have had loads in, lots say "it needs a new roof pump" . I have replaced one! It's nearly always something else.

 

[Uncle Benz]

+1 see lots of these broken. Rather pricey too, although I think ops fault would be somewhere else as the roof wouldn't go up with this broken?

That switch is a three wire, two pole switch. It monitors the position of what merc call the "rear bow". The rear bow is the back section of hood with the rear glass window in it. The switch tells the ecu it's up or down. Usually a fault here means the rear bow lifts up, but the ecu doesn't see it as lifted up, and the rear deck won't then raise, as it can't see the bow has lifted. It can however fail with the rear bow down. The switch isn't closed, so the ecu doesn't know the bow is down. In that case it won't unlock the bow or attempt to lift it, which is the scenario the OP describes. His windows drop when he unlocks the header rail, so I think the microswitch in the header rail is working. This switch will hold roof operation off too, but with the window drop working I think this switch is ok. The bow switch is the next one in sequence. I'm not saying it's definitely that, but logically it would be my next check.

 

[alexanderfoti]

Does the window drop not happen on the switch rather than the manual roof lock?

 

[Uncle Benz]

Long ago I detailed all this out for another member, but it was before the upgrade, so doesn't find now with a search. I think his name was Abdul. I'll try a Google search for it