r129 driver seat issues

[g60rge]

my seat doesnt slide backward or forward

it tilts the base fine

the back rest goes forward but not backward

the head rest goes up and down ok


does this sound like a switch or control module problem?

how can i test this?

common fault?

 

[Top Cat 500]

seat

If you are stuck at the back end of the seat travel, the back won't tip back. However, this sounds like a module problem if all the other switches seem to work.

Getting to the switch block means removing the door card, not too difficult, but a bit of a phaff: but I don't think you can access individual switches, you would just have to replace the whole switch unit. If you can get a wiring diagram, it might be possible to check each switching action

The control module is under the seat base, which is easy to remove (two 10mm machine screws, one either side at the front), but you would still need a system diagram to identify which module to replace.

With the seat base out, you could just check whether it is jammed at the end of its travel. You never know, a bit of muscle might just fix this!

 

[Merc125]

Electric Motors?

You can check if working with a multimeter

Check fuses first.

 

[television]

I would say that all of the problems are to do with the seat motors and or switches. Switches are worth cleaning with a non drying switch cleaner.

Another fault can be the connections on the switches.

 

[g60rge]

ive had the two big plugs on the door switch the wrong way around and the seat slides forward but not back so it deff cant be jammed and the motor must be working.

ive taken the switch apart and re soldered some dry joints which got the headrest working..

il open the switch plugs cover and check the connections are good

the door switch itself once seperated from the wooden cover cannot be opened to reveal the actual switches otherwise it will break only the back of the pcb is visible once the rear is prised open

what is the switch block you refer to that needs the door card removing?

thanks for the replies

 

[television]

The ones in the door cards.

 

[Top Cat 500]

I have just spotted that you have the early model, so the door cards are different from mine, but it sounds as if you have got to the switches, or at least the pcb holding them.

It could be a broken wire between the switches (what I called the switch block before) and the control module, esp as it flexes through the door hinge. If you can get to both ends with a meter you could check the continuity. This is a frequent problem with the 3rd brake light in the boot lid, but easily fixed there. Here it might be more of a problem.

It could be faulty contacts in the actual switch, so you might be able to fix it if you dismantle the switch unit, but be prepared for not being able to reassemble it and having to replace the whole unit. Critical little springs have a habit of launching themselves into oblivion!

 

[g60rge]

revisiting this problem..

i got hold of a replacement switch - obv second hand so no way of knowing if it works or not

all functions work except slide function. forward or back

i have two spare seats so i have a spare motor to plug in, il do this soon

 

[television]

The wires can get damaged as well.

 

[g60rge]

i would say the motor definitely works as i just tilted the seat all the way back and the seat started to slide forward, won't do this again as i will not be able to slide it back again.

would there be any info on what colour wires and what plug on the under seat module are for the seat slide function from the seat switch to the module so i can test them for breaks? i have no idea to work out which its is..

 

[g60rge]

Still have this problem

 

[LostKiwi]

Have you swapped control modules left to right and tried it?

 

[brianbrian]

You can move the seat back and forward manual, by turning the shaft.

 

[brianbrian]

Also squirt the switch with electrical cleaner it may do the trick.

 

[g60rge]

it was a dry joint on the seat control module

only took me 4 years to get to the bottom of this hahaha

 

[John De Bock]

it was a dry joint on the seat control module

only took me 4 years to get to the bottom of this hahaha

Did you resolder everything or did you find the exact spot?

 

[Mia Beach SL500 2002]

You can move the seat back and forward manual, by turning the shaft.

I have a 2002 SL500 and I cannot see how I could manually move the seat back - I have the same issue seat moved forward even on using switch for backward move. Thanks for any help !!! I don't fit in my own car anymore to bring it to garage!

 

[LostKiwi]

I have a 2002 SL500 and I cannot see how I could manually move the seat back - I have the same issue seat moved forward even on using switch for backward move. Thanks for any help !!! I don't fit in my own car anymore to bring it to garage!

You're probably better to start your own thread. This one is for a totally different car to yours.

 

[Mia Beach SL500 2002]

You're probably better to start your own thread. This one is for a totally different car to yours.

Thanks for your response. I am actually precisely matching the headline which states R129 seat issues where someone suggests to move the seat mechanically which I try to find out how to do this. Of course I need desperately help and if starting a new thread will lead to any insight I would be very grateful. Thanks!

 

[LostKiwi]

Thanks for your response. I am actually precisely matching the headline which states R129 seat issues where someone suggests to move the seat mechanically which I try to find out how to do this. Of course I need desperately help and if starting a new thread will lead to any insight I would be very grateful. Thanks!

A 2002 is either an R230 or a very very late 129. Which is yours?