W124 Central Locking Diagnosis

[tjamesbo]

Central Locking has not been working on the W124 and its time to Sort it
According to the Manual The Fuse is a Red 16A in C
Checked it and its OK decided to replace whilst there as I know they Corrode on these cars
My symptoms are that Nothing locks or unlocks unless its done manually and I cannot hear the pump operating at all
I have found the Pump hiding under the rear passenger seat and thought I would check
1 is it getting 12V supply
2 is it getting a valid switched supply from the drivers door or anywhere else

I have 12V at the main connector so thats a tick
at the switching connector there are 6 wires that go to a three pin connector I'm guessing pair for the 2 front doors pair for the two rear doors one for the boot and one for the filler cap ???

Not sure what i'm now looking for for the next stage diagnostic
what kind of signal comes to this connector a transient 12v as the key is turned in the drivers door lock or a permanent 12V
or can I jumper a 12V feed to one of the pins and see if the pump triggers??
Boyd

 

[mej]

I would fire 12v at it as per the diagram attached. You seem to have covered everything else, and the pump often runs briefly on start up.

 

[tjamesbo]

Looks like its snookered as I've just found 12V on one of the feeds so looks like its an imput but still nothing operating just remembered reading somewhere the contacts can stick inside and the way to free them is to drop the thing on the floor so possibly thats the next step although worth trying a 12V feed on the other pins first

 

[tjamesbo]

opened up 2 relay contacts inside move freely so does the vacuum sensor spring switch
Thats about the limit for me so looks like its an ebay from germany jobbie at approx £40 inc Postage

 

[mej]

Does that mean it won't run with the 12v directly applied? If so, have you tried applying the 12v and 'jiggling' the wires at the same time? Any brownish/poorcontact solder on the back of the PCB which might benefit from reheating?

 

[television]

Its normally the motor that fails, I always unsolder the wires and try across the battery to see if it runs, the rest of it seldom fails.

 

[yeh yeh]

I tend to agree with mej, it could well be just a dry joint in the printed cercuit, take a close look at the solder joints, they should be shiny, if you see a cloudy looking joint apply a bit of solder to it and make sure it's shinny when cooled.

 

[tjamesbo]

Eek suprise the Motor Runs with 12V direct, but wont run if 12V also applied to any of the three pin signal input connector pins on the board . Re piccie below The Pcb is substantially corroded top Left and Top Right Top right is negative feed to Relay, on the other (left top ) side its some sort of small black tubular component and there's green corrosion on the Component side The Tracks look worse than the Joints not sure if its salvageable might try to solder the connections again but soldering PCB's not something I have experience of but its Knackered anyway so nowt to lose

 

[tjamesbo]

Just looking at the Photo more detail can be seen now its uploaded and on zoom Theres a piece of Track blown in the middle so looks like its curtains for it Time to fork out £25 + £14 postage for one from Germany ( E bay )
cant at moment locate anything cheaper in the UK

 

[television]

Post it to me and I will fix it free of charge

 

[television]

As you are not far from me,,, pop down with it and I fix it on the spot

 

[tjamesbo]

I'll look forward to that malc , might see you sunday, but my timing for sunday now looks dodgy as wifes just informed me we have a christening at midday, but I would liik forward to a trip down to see you Can you PM me your address / contact tel no and I'll give you a ring or email me I'm on your e-mail it starts boyderoo .........

 

[DREAMER NO2]

Rob at threepointedparts@hotmail.co.uk 07737360966 Rob as lots of them .

 

[television]

I am not 100% clear on the meet, but tjamesbo will be going past my door to get there, Maybe he would like to drop off on the way home and I will fix it for him

 

[tjamesbo]

Hi Malc I can go past your door and drop it off but need your address or contact no , or I can see you there I will have to leave the meet by about 11 ish as I have a christening to attend
Boyd

 

[television]

Hi Malc I can go past your door and drop it off but need your address or contact no , or I can see you there I will have to leave the meet by about 11 ish as I have a christening to attend
Boyd

Things all went wrong at my end, can you post it to me, just the postage cost.

 

[tjamesbo]

Got your PM thanks I'll pop down probably next week

 

[tjamesbo]

here we go again only 12 mths or so later No central Locking again fuse Ok so out comes the unit again GRRRRR!
Cant seem to open The wiring Diagram PDF on the earlier post ... does this still work on the new Format forum ????
Boyd

 

[LostKiwi]

Works fine for me? Just opened straight away on my phone.

 

[tjamesbo]

OK got it now the link / download is working now . I think I'm just going to replace the pump with the unit Malc repaired and see if it works, might have a leak somewhere and possibly the unit is being overworked ( up to its max cut off time ) if it works I'll time it to cut off ,if not onto the circuit diag and out with the voltmeter
what I bind without central locking How did we manage in the old Days when the only car with central locking was the 2CV and that was because you could lock all the doors from the drivers seat