Electric seat not moving backwards

[mr vandango]

Hi guys, as per title, my drivers seat won't move backwards. When I picked the car up at the weekend it moved back 3 inches or so and then stopped dead. It wouldn't move forward or backward from then. T

Today I removed the seat base and tried tapping the motor but this had no effect. I removed the switch from the door card to see if I could investigate that but it revealed nothing at all.

When I put it all back together (what a nightmare the base is to refit!!) I tried the switch and it moves forwards now, only trouble is it still won't go back, and it's even further forward than before I tried to sort it out. There is no click from the relay when the switch is operated, so my guess is that it's the switch that's gone faulty. Can anybody confirm what I am thinking? It is just so uncomfortable to drive - there are old ladies out there laughing at me

Before I go ahead and buy another one, I'm going to have a go at re-flowing the soldered joints on the pcb - you never know huh?

 

[Belldarr]

Hi - is it W208 or W209 model?

DB

 

[mr vandango]

Hi there - It's a 208

 

[Belldarr]

Hi - It could be the sensors that tell the seat that the back has been tilted forward (to let people into the back seat). When you tilt the seat forward does the entire seat move forward on the track? Also will it go backwards along the track when you tilt the seat back? My old CLK (w208) seats did move backwards and forwards when allowing people in and out the back - you may have to pull the seat release up as far as it will go (carefully as they can come off) and also when you put the back of the seat into it's proper position push down on the seat release to get it to move backwards into the previous position on the runners. Possibly try the passenger seat if that all works as it should to see what should happen when using the seat like this.

The fact that you can go forward means the motor is ok - also try and check the toothed tracks for coins etc.

If you have a multi-meter you can test the switch? it could be gunked up but I think the problem is the seat thinks it is still tilted forward - good luck with the problem though and I hope I have helped.

D

 

[mr vandango]

Wow, that's plenty of information, I will give your suggestions a try. I had noticed when I pull the seat back lever it only moved the back, it doesn't slide forward like my old Astra coupe used to. I will let you know how it goes. Many thanks!

 

[gbjeppm]

If its had battery off recently, it needs to be reset.

If it moves forward move it forward until it stops, and keeping holding for 4/5 seconds.

Then try moving back, and hold when it moves no more.

Reset procedure in the manual, there is also one for the windows.

 

[mr vandango]

If its had battery off recently, it needs to be reset.

If it moves forward move it forward until it stops, and keeping holding for 4/5 seconds.

Then try moving back, and hold when it moves no more.

Reset procedure in the manual, there is also one for the windows.

Thanks for that.. It did have a flat battery when I picked it up, so I've just tried your reset suggestion with no joy! I can hear the relay clicking when the switch operates to move it backwards, but no movement at all. I'm assuming this rules out the switch being at fault, and the tracks are clear as far as I can see.

I tried the seat back trick, and I can hear it operating something under the base when I really pull on the lever, but the seat won't slide as it should. It stays rock solid.When tilted forwards to let people into the back, does this disable the motor in some way to allow it to slide forwards for access?

I'm really lost now, as it appears that all is well, it's just refusing to slide back! I'm going to try the reset one more time again now!

 

[gbjeppm]

If you have the manual check it in case i got it slightly wrong, but basically it needs to be retaught where to stop on both extremities after loss of power from the battery.

 

[mr vandango]

Ok, so I've just tried the reset again and no joy, but I did notice that the 'click' from the base relay is very quiet and almost inaudible, whereas the ones for the seat back and heat rest are much louder and make a very positive noise.

Could it be a relay issue, where it's not switching effectively or adequately? Can they be changed?

 

[gbjeppm]

i would start with the switch first, take it out and use switch cleaner, the motors are pretty robust. I know nothing about the relays.

 

[mr vandango]

Ok, thought I'd give a quick update in case anyone stumbles across this when researching the same problem.

So my drivers seat wouldn't budge after moving a little, it just gave up altogether, and was stuck all the way forward. All other functions were working as they should.

I tried:

removing the seat base and checking for loose chaffed wires
knocking the motor with a hammer whilst operating the switch (middle one of the three)
removed and cleaned door switch
reflowed the solder on the door switch pcb
resetting the door switch

After digging around a little, it seemed that there were issues for other mb owners when a battery had gone flat or been replaced. Mine had had a brand new battery put in when I picked it up. With this in mind, in a clutching at straws moment, I disconnected the new battery and left it off for an hour to reset. When I connected it back up I did the switch reset once more and hey presto the seat started to move!

This may only be a temporary solution, as I've had to do the switch reset once more since then as it stopped moving once more, but at least the car is driveable now, and if I need to get access to the seat base screws to replace the motor it won't take an hour to do them backup like it did when it was jammed all the way forward. My issue could still be a dodgy switch or motor, but at least I got somewhere in the end!

 

[sjmaxwell]

Could also be a bad earth on that part of the loom. From memory it is screwed in the passenger foot well between the seat and the additional control modules at the very front of the space. May be worth checking for corrosion?

 

[mr vandango]

Could also be a bad earth on that part of the loom. From memory it is screwed in the passenger foot well between the seat and the additional control modules at the very front of the space. May be worth checking for corrosion?

I didn't even think of a bad ground thank you! Might explain why it's seemingly intermittent. Do you know if that loom contains other electrics that may be also affected if it is bad? I only ask as I have no voltage at the glove box light.

 

[sjmaxwell]

I didn't even think of a bad ground thank you! Might explain why it's seemingly intermittent. Do you know if that loom contains other electrics that may be also affected if it is bad? I only ask as I have no voltage at the glove box light.

I fitted memory seats to my W208 about seven years ago and just remember that the memory seats had there own loom. I do think that there were other earths on the same point but I could be wrong!

 

[armanmal]

Hi guys, as per title, my drivers seat won't move backwards. When I picked the car up at the weekend it moved back 3 inches or so and then stopped dead. It wouldn't move forward or backward from then. ?

I see the post is 1 years old but I have same problem with my CLK320 w208 1998.

I already found a problem. It is in a main block of driver seat control. 2 relays are dead and 2 moves of seats are not working. But when you switch connections you can control it. So the solution is to exchange relays

The matter is that I can not find it to buy both in my country or online.
Can anybody help to get relays?

Please have a look on photo. Siemens relays - main unit and 4 others

 

[KevinGP]

Ok, thought I'd give a quick update in case anyone stumbles across this when researching the same problem.

So my drivers seat wouldn't budge after moving a little, it just gave up altogether, and was stuck all the way forward. All other functions were working as they should.

I tried:

removing the seat base and checking for loose chaffed wires
knocking the motor with a hammer whilst operating the switch (middle one of the three)
removed and cleaned door switch
reflowed the solder on the door switch pcb
resetting the door switch

After digging around a little, it seemed that there were issues for other mb owners when a battery had gone flat or been replaced. Mine had had a brand new battery put in when I picked it up. With this in mind, in a clutching at straws moment, I disconnected the new battery and left it off for an hour to reset. When I connected it back up I did the switch reset once more and hey presto the seat started to move!

This may only be a temporary solution, as I've had to do the switch reset once more since then as it stopped moving once more, but at least the car is driveable now, and if I need to get access to the seat base screws to replace the motor it won't take an hour to do them backup like it did when it was jammed all the way forward. My issue could still be a dodgy switch or motor, but at least I got somewhere in the end!

How did you reset the door switch !
?