Serndipity

Keep in mind that there are many switch interlocks that may keep the motor from operating (see post 16 above).

Additionally, the hydraulic motor relay fails much more frequently then the motor itself (e.g. due to switching high current the contacts fail).

The fuel pump relay is of the same type, so you can temporarily use it to see if the hydraulic unit relay is the problem.

See attached for more information.

serlock

Is that relay in the trunk together with fuses? If so, its 1 minute job. I will try. Today i was driving and now windows wont move down after i press red button which keeps blinking slowly while driving. There must be some sensor or switch, relay - faulty.

Top Hydraulics

serlock,

thank you for the additional detail. I will address the question of testing the pump motor below, as requested. You were mentioning a lot of noise, but that may be the normal noise level from the pump. If the headrests were moving before, then obviously the pump was still working. It is possible that the pump motor was about to burn out and the pump could produce enough pressure only to move the headrests aka roll bars, but not enough pressure to unlock the rear bow for soft top movement. Normally, the 40A fuse would blow once the electric motor on the pump has seized. However, if you hold the button only for a short time, then the fuse does not necessarily have to blow.

Since you already have access to the pump, you could briefly "hot wire" it. Take out the relay and put a jumper where pins 30 and 87 of the relay were in the connector. If the pump runs now, then it was not the problem.

I am attaching below a picture of an electric motor that has started melting inside, and a picture of a jumper on the relay connector.


Fully agreed. Checking out the signals from the micro switches is probably what the diagnostics will come down to.

Agreed, swapping in the fuel pump relay is a good test for the relay. It is not necessarily a test for the pump motor. Obviously, swapping relays will only make the pump run if there is a signal telling the relay to switch ON in the first place. Serlock mentioned clicking in the rear - that was probably the old relay at least trying to activate. The two most common failure modes for the relays are burnt contacts not providing enough conductivity, or the contacts welding together (not likely in your case, since the fuse is still intact and it normally blows after the motor has run for too long).


Klaus

www.tophydraulicsinc.com
http://www.tophydraulicsinc.com/en/23-w208-clk

Top Hydraulics

The relay is next to the pump.

Check in your owner's manual if your model CLK has the partial window drop when you open the doors, and how to reset (synchronize) the windows after the battery has been low or disconnected.

Klaus

www.tophydraulicsinc.com

serlock

Ok Thanks Klaus! Im gonna do wire jumping and relay replace thing right now, will be back with results in 20 mins.

serlock

Now guys you were absolutely right! That was the relay, i put it and motor is working. But now when i try to lower the headrest, i see how hydraulics is trying to lock the lock which is outside of the passenger seat. But headrests would not go down. I see how metal hood is going slightly down because hydraulics is pressing the lock. What this could mean ? same thing happens when i press red button as well. My guess is that system is out of alignment. And my car does not have the slight window go down after i open door thing. It does not drop.

Serndipity

serlock

Great, progress....that the motor is OK.

However, I'm not quite following everything you wrote.

Sounds like your roll-bar is up and can't be lowered by the operation of the hydraulic system.

The following link may help.

https://mbworld.org/forums/clk-class...umps-help.html

In post #3, you'll find additional information on the roll-bar theory of operation.

It's possible that:

1. the built-in springs mechanically deployed after sensing a driving condition (e.g. crash, pothole etc.) and are now locked in the up position.

2. one of the electrical position/limit switches are faulty or misaligned.

Also see post #16 in this thread (explains all the switch functions and operating conditions).

PS: If you search further in this forum, you'll find information on being able to purchase a replacement relay, inexpensively, from a local auto parts store.

serlock

I will try to explain better. Whenever i try to lower the headrest -I push button of headrests. Instead of lowering - the motor is suplying the pressure to the lock which is behind the wall. I see how lock is moving. same happends when pushing the red button. I will try to disconnect the battery and connect again. Will see what happens.

serlock

Ok, so disconnected the battery. That helped. Now headrests move up and down like it should. Thanks to you guys. Now when im pushing red button - it starts to blink fast and nothing elses happens, just a relay click.

Serndipity

On USA models, after reconnecting the battery you have to resynchronize; the front seats and head restraints, the power windows express feature, the electronic stability program (ESP) as well as set the clock and radio code. Details on how to do all this is in the owners manual.

Additionally, if the power top was in a partially open position, it also has to be synchronized. To do so, raise and lock the soft top manually, the procedure on how to do this is also explained in the owners manual.

serlock

The roof was always closed. I dont have a manual, maybe you know a link where i can donwload it ?

So there are 9 sensors in total. I must check them all i guess...

Serndipity

In the US, we can download owners manuals from the MB-USA web site.

www.mbusa.com/‎

Not sure what the differences are between US and EU models (e.g. safety, emissions, other equipment?).

My guess would be that, in regard to the power roof operation, they are the same.

You mentioned purchasing the car with the power roof inoperable and don't know what prior repair efforts were tried, or if the faulty hydraulic motor relay would present the same condition as disconnecting the battery.

It may be a long shot, but as a next step, I would try manually lowering and raising the roof once, to see if that resynchronizes the power operation.

serlock

Ok, i will get the relay. Then i will lower the roof. See what happens then. Thanks! After i make this happen ill write a pdf on how to check everything

GatorMB

Circuit 30,

Power circuit for pump control relay, Coming kinda late into this post but the relay connector required replacement.
The jammed latch would have been a good starting point as well. Leaks etc... your getting close.

The Hydraulic Pump relay is typical part that can be purchased in the local auto parts store provided the current rating of the contacts matches that of the original normally 30 amps is max on these.

The pigtail for the relay matches many manufacturers of aftermarket fog/drive lighting systems. I used this relay in many aftermarket applications on various systems like cooling fans/radio amps on/off etc... Relays protect low voltage circuits by utilizing low voltage request to high current output like motors and lamps.

Cheers, Late Gator

serlock

Thanks Gator, is Christmas, all is closed. Will proceed after it. I will definetely get to it.

Top Hydraulics

Gator,

there is some good information in your post, but I'm not sure if it's in the correct thread or missing some background info. You are addressing fellow member Circuit 30 and remarking that the relay connector required replacement, so you must have solved a similar problem in your CLK...

The pump & controller manufacturer generally specifies a protective resistor in the relay, (between pins 85 and 86), a constant current capacity of 30A, and a surge current capacity of 60A for their systems' relays. You can make some concessions on the surge current.

The pigtail for the relay (meaning the connector that the hydraulic pump relay p/n A 002 542 13 19 aka A0025421319 or 0025421319 plugs into) can indeed be purchased in parts stores, although it will not have all the Mercedes mounting tabs on it, and you may have to slice the original wires. Watch out for the wires gauges when splicing, and make sure to have good contact in your splice. Instead of replacing the whole pigtail, one might be able to fix the bad contact by carefully cleaning it and carefully bending the damaged metal connector inside the pigtail such that it provides good tension again on the mating pin of the relay.

One danger of jumping the pigtail as I had described before, is that the contacts could get damaged if there is a huge current flowing (in case the motor is already burning out). However, such jumping-damage usually occurs on top of the contacts, whereas the metal contacts inside the pigtail grab the relay on the inside. Nothing I haven't been able to clean up again if there ever was major sparking...

Just for reference, below is the picture I posted earlier of the pigtail and where to jumper it:


Merry Christmas to all!

Klaus

www.tophydraulicsinc.com

serlock

Got the manual and read some articles. Ok, so to synchronise windows its easy. Roll them up, and hold button for 2 more sec. For synchorinisng the roof im not sure if i understood, but i guess its done by rolling roof down and up manually and then it should be synchronised. great link on all w208 reset procedures.:

http://www.garaget.org/forum/viewtopic.php?pid=2226428

Serndipity

Yes, resynchronizing the roof is done by lowering and raising the roof manually, as described in the owners manual, where the procedures necessary to release the hydraulic pressure, lock/unlock the soft top cover are described.

serlock

Ok, so i got a relay. Now headrests work fine. Now, when i raised down roof manually. The red button stopped blinking, and went off. When roof was up it became red, and when driving it blinks + a sound beeps for 5sec. Also if i raise the headrest while driving it starts to sound beeping for 5 sec. also. Ive done a reset of windows (heard a "Click"). Also ive done manual roof up and down. What now i should do to trace the problem? When im pressing red button nothing happens only it starts to blink, windows wont go down.

Serndipity

Have you reviewed the information attached in post #16?

It explains the functionality of the main switch light diagnostics and more importantly, the proper status for each switch and hydraulic cylinder, during each stage of the power roof operation.

serlock

Thanks, Serndipity, so when vehicle is stationary - lamp is illuminated, when vehicle is being driven - lamp is illuminated and flashing. So it comes down to - that soft top is not properly locked.

Ok I see on 12th step, the switch S84/11 has to be saying the soft top is locked. (the one in the windshield).

Also other switches have to be sending signals soft top is closed:

S84 / 13s1
S84 / 15
S84 / 16
A25/s1
A25/s2

Their locations we know from others posts with photos. I will copy those pictures into 1 pdf document so it will be easier to find in the future.

My question is: how do i properly check the switches, so i take the multimeter, switch it to show ohms (resistance) and probably best is to find the very end of place (might be the control unit? i hope those wires have different colors) where those wires go and then put multimeter on wires and see changes when switch is pressed/depressed, am i right ?


After writing this, my friend did a star diagnosis, there is a fault saying that control module n52 is defective ( which is quite rare here in junk yards, and a new one will cost a lot i guess.

Serndipity

OK on having the STAR diagnosis (e.g. N52 controller fault). However, It's unclear if it actually checked the internal circuitry or just that it didn't have the correct inputs/output/switch conditions.

A new controller would be very expensive and because of limited cabriolet production, finding a working used unit would likely be difficult.

So I would still proceed by with checking for the required switch operation/status during the 12 stages of the power roof operation.

Normally a switch is either open (high resistance) or closed (zero or very low resistance.

I've previously read where the power roof wires can become frayed or make a poor connections overtime, checking at the unplugged N52 connector is best. However, this is not possible without it's pin assignment diagram (maybe the WIS shop manual has this information).

I've attached additional information on the S84 main switch. Note that when pressed, an electrical current flows to ground from the N52 controller. This current has different values, corresponding to the switch resistance that allows the controller to recognize the swich position (e.g. voltage coding). Unfortunately, without see an electrical schematic diagram of the N52 internals, I'm not sure how how this works (e.g. could just be the status of the switches on the controller input side).

I'll try to attach a larger, more readable block diagram of the soft top system as well.

For more information on the power roof limit/position switches, see the document in post #10 at https://mbworld.org/forums/clk-class...clk-320-a.html

The S84/11, left locked left limit switch is on page 9 of that document, as well as an included attachment.

Also see post #6, on how to access S84/11 at https://mbworld.org/forums/clk-class...hemselves.html

In that case, the problem was that it was lose and needed adjustment.

Also make sure that the luggage cover basket is in place and properly engaging the position switch (see attached). The only issue I have had with my power roof not operating, was that even though the cover was correctly in place, it's roller wheels were not in the guide channel and the switch was not activated.

serlock

Ok, so today i was standing by the repair garage, waiting for my queue, and i played with that switch, and all of a sudden, windows went down, soft top opened, as well as rear bow, roof opened completely. And it was raining, and after that roof could not close back. I had to closed it manually lol. So it means there is some switch with a bad contact, causing this. I attached N52 pin out diagram but for me its too difficult to understand maybe you will get it.

So the luggage cover switch is fully switched i have glued it with a tape to be sure. (because when its open - red switch blinks FAST)

S84/11 - the switch on the windshield i have accesed yesterday by removing the plastic around it. The switch is being pressed beautifully when ST is closed. And opened - once ST is opened.

So im getting there slowly but surely lol. Ill try to track the wires by color on the unplugged N52 connector.

serlock

Ok, another update. It was the sensor which is on a RIGHT BOW HINGE. it was not working properly. I fixed it and roof works flawlessly. However, the red button keeps blinking while driving. I am 100% sure its a windshield sensor - contact must be broken somewhere. But im glad i did it. Thanks a lot guys!

Serndipity

OK.... more and more, the problem appears to be a faulty(intermittent) limit/position switch, which could be due to a bad switch, wiring connection (ground?) or mis-alignment.

The controller will sense each switch, for the proper operating condition, during each stage of the power roof operation operation before starting a succeeding stage.

Verifying every switch condition/status vs. the corresponding 12 stages of roof operation, shown in post in #16, is now your best friend.