Central locking pump w202 wiring

John Cunningham · 12-10-2008, 05:45 PM

Hi. I am trying to find a wiring diagram for the pump or even a list of which coloured wire goes where. it is for a 95 w202 c180. Haynes manual seems not to cover it.

My cental locking has never worked on the car since I had it. Pneumatics ok I have tested them. I get 12v from some of the pins on the connectors and I have found the dashboard switch wire. I can't seem to locate the wire from the door lock switch etc hence a wiring diagram would be good. Looking at the board in the pump there are two relays so they may be a suck and a blow wire from the locks and switch, but I am guessing.

My the pump was seized. it is now un-seized but I thought I'd check the wiring before I buy a new pump.
Any help is appreciated.
Thanks
John

Dec · 12-10-2008, 11:08 PM

There is a Central Locking Control Module in the boot, hidden behind battery, (sometimes called a Comfort control unit, see Haynes manual page 11*23 bottom right.
I believe this unit talks to the pump, some of the wires go from it to the pump, I take it all doors and boot and petrol flap aren’t working, this would seem a likely suspect in that it could have gotten wet/damp due to its location, might be worth checking the wires of which there are quite a few.

Wiring diagrams on Mercs are a very rare commodity.

Dec

John Cunningham · 13-10-2008, 12:06 PM

Thanks Dec.
I have had a look at the comfort control unit. All looked ok from the outside. When I looked in the boot fusebox there was no fuse in place for it. I put in a 7.5A fuse and now I can lower and raise the windows from the key, which is something that I couldn't do before.
Central locking still not working.
I know this is not a simple system and is problematic, which is why I am surprised there isn't a self written guide on the tinternet. I can't find anything on fault finding the system.

Dec · 13-10-2008, 09:39 PM

Hi John,
The comfort control unit seems to be a complete mystery to every one, the only fault that I have with my car is that the windows/sunroof won’t close automatically, If open, when I lock the car with key fob, However on very hot days in summer, like 25c, the work fine but as soon as the car body cools down the automatic closure stops working. Could never get to the bottom of this so it must be a loose connection somewhere that is influenced by the heat.
Anyway back to your problem, I was looking at my own VIN on the Russian site, there is a comfort control relay, Number 50, but I couldn’t find this in my own car when I had a quick look this evening, maybe you might have better luck, that is if you are supposed to have one too.

Your problem might be something simple like this as your entire door central locking is not working.

Dose the pump ever make any sound?

Dec

nick mercedes · 13-10-2008, 09:58 PM

Quote:

Originally Posted by John Cunningham

Hi. I am trying to find a wiring diagram for the pump or even a list of which coloured wire goes where. it is for a 95 w202 c180. Haynes manual seems not to cover it.

My cental locking has never worked on the car since I had it. Pneumatics ok I have tested them. I get 12v from some of the pins on the connectors and I have found the dashboard switch wire. I can't seem to locate the wire from the door lock switch etc hence a wiring diagram would be good. Looking at the board in the pump there are two relays so they may be a suck and a blow wire from the locks and switch, but I am guessing.

My the pump was seized. it is now un-seized but I thought I'd check the wiring before I buy a new pump.
Any help is appreciated.
Thanks
John

The pumps are reliable, so you should be able to find one at your local breakers for not a huge sum.

The pump is no 1 suspect.

John Cunningham · 14-10-2008, 10:39 AM

Hi Guys,
Todays developments. whilst locking and unlocking the car the door buttons popped up. I didnt hear the pump and it hasn't happened again. when i turn the key i can see the rear door buttons quiver. This tells me that the control circuits must be ok. Ihave never got the pump to work, whilst wired up , but i have tested the actual pump part on its own and it goes like the clappers. there is a surprising amount of circuitry and relays in the pump box. Maybe the cut out relays are tired.
pity about the wiring diagrams as an hour with a multimeter would isolate the problem. i suppose it is now trial and error replacing bits. pump first.

Dec · 14-10-2008, 01:23 PM

The way I would be looking at it is that the comfort control isn’t communicating with the pump, the wires that go into the pump can be traced back to the comfort control module if you were to undo the two plastic nuts that hold it in place and examine all the connections. You will need to remove battery.

While the pump runs when you wire it up independently, that is no guarantee the whole unit is working properly, for example when the pump receives a signal it is supposed to run for a set time like perhaps 3 or 4 seconds so maybe that element is faulty.

Operating the key in the passenger door on my car doesn’t do anything except unlock that door, it doesn’t have any effect on the other doors or involve the pump running.

Dec

John Cunningham · 15-10-2008, 10:48 AM

central locking is now working sporadically by the key. Nothing via the dash board switch. Picked up a second hand pump. and wired in. can now hear the pump running and relays clicking when using dashboard switch. problem now is new pump is bosch old pump is hella . Hella has a straight connector and a clip, bosch has a knobled straight connector (pneumatic type). Why is everything so hard all the time. same model, same year different connector!!. Ill try and open them up and see if I can transfer the casing. Otherwise try and make an adapter.

Dec · 15-10-2008, 11:15 AM

Quote:

Originally Posted by John Cunningham

Why is everything so hard all the time.

That’s Murphy’s law, we are all governed by it, at least you are making progress, eventually you will crack it.

Dec

12-10-2008, 05:45 PM	#1
John Cunningham New Member Join Date: Feb 2008 Posts: 19	Central locking pump w202 wiring Hi. I am trying to find a wiring diagram for the pump or even a list of which coloured wire goes where. it is for a 95 w202 c180. Haynes manual seems not to cover it. My cental locking has never worked on the car since I had it. Pneumatics ok I have tested them. I get 12v from some of the pins on the connectors and I have found the dashboard switch wire. I can't seem to locate the wire from the door lock switch etc hence a wiring diagram would be good. Looking at the board in the pump there are two relays so they may be a suck and a blow wire from the locks and switch, but I am guessing. My the pump was seized. it is now un-seized but I thought I'd check the wiring before I buy a new pump. Any help is appreciated. Thanks John

12-10-2008, 11:08 PM	#2
Dec Hardcore MB Enthusiast Join Date: Jul 2004 Car: C180,A. December '94 84k Posts: 873	There is a Central Locking Control Module in the boot, hidden behind battery, (sometimes called a Comfort control unit, see Haynes manual page 11*23 bottom right. I believe this unit talks to the pump, some of the wires go from it to the pump, I take it all doors and boot and petrol flap aren’t working, this would seem a likely suspect in that it could have gotten wet/damp due to its location, might be worth checking the wires of which there are quite a few. Wiring diagrams on Mercs are a very rare commodity. Dec

13-10-2008, 12:06 PM	#3
John Cunningham New Member Threadstarter Join Date: Feb 2008 Posts: 19	Thanks Dec. I have had a look at the comfort control unit. All looked ok from the outside. When I looked in the boot fusebox there was no fuse in place for it. I put in a 7.5A fuse and now I can lower and raise the windows from the key, which is something that I couldn't do before. Central locking still not working. I know this is not a simple system and is problematic, which is why I am surprised there isn't a self written guide on the tinternet. I can't find anything on fault finding the system.

13-10-2008, 09:39 PM	#4
Dec Hardcore MB Enthusiast Join Date: Jul 2004 Car: C180,A. December '94 84k Posts: 873	Hi John, The comfort control unit seems to be a complete mystery to every one, the only fault that I have with my car is that the windows/sunroof won’t close automatically, If open, when I lock the car with key fob, However on very hot days in summer, like 25c, the work fine but as soon as the car body cools down the automatic closure stops working. Could never get to the bottom of this so it must be a loose connection somewhere that is influenced by the heat. Anyway back to your problem, I was looking at my own VIN on the Russian site, there is a comfort control relay, Number 50, but I couldn’t find this in my own car when I had a quick look this evening, maybe you might have better luck, that is if you are supposed to have one too. Your problem might be something simple like this as your entire door central locking is not working. Dose the pump ever make any sound? Dec

14-10-2008, 10:39 AM	#6
John Cunningham New Member Threadstarter Join Date: Feb 2008 Posts: 19	Hi Guys, Todays developments. whilst locking and unlocking the car the door buttons popped up. I didnt hear the pump and it hasn't happened again. when i turn the key i can see the rear door buttons quiver. This tells me that the control circuits must be ok. Ihave never got the pump to work, whilst wired up , but i have tested the actual pump part on its own and it goes like the clappers. there is a surprising amount of circuitry and relays in the pump box. Maybe the cut out relays are tired. pity about the wiring diagrams as an hour with a multimeter would isolate the problem. i suppose it is now trial and error replacing bits. pump first.

14-10-2008, 01:23 PM	#7
Dec Hardcore MB Enthusiast Join Date: Jul 2004 Car: C180,A. December '94 84k Posts: 873	The way I would be looking at it is that the comfort control isn’t communicating with the pump, the wires that go into the pump can be traced back to the comfort control module if you were to undo the two plastic nuts that hold it in place and examine all the connections. You will need to remove battery. While the pump runs when you wire it up independently, that is no guarantee the whole unit is working properly, for example when the pump receives a signal it is supposed to run for a set time like perhaps 3 or 4 seconds so maybe that element is faulty. Operating the key in the passenger door on my car doesn’t do anything except unlock that door, it doesn’t have any effect on the other doors or involve the pump running. Dec

15-10-2008, 10:48 AM	#8
John Cunningham New Member Threadstarter Join Date: Feb 2008 Posts: 19	central locking is now working sporadically by the key. Nothing via the dash board switch. Picked up a second hand pump. and wired in. can now hear the pump running and relays clicking when using dashboard switch. problem now is new pump is bosch old pump is hella . Hella has a straight connector and a clip, bosch has a knobled straight connector (pneumatic type). Why is everything so hard all the time. same model, same year different connector!!. Ill try and open them up and see if I can transfer the casing. Otherwise try and make an adapter.

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