CL500 "Front seat backrest unlocked" warning

[Roadtoad]

If you buy another seat how do you know you wont have the same problem if not now in a few months time ? This problem is very common and caused by wear due to movement of the seat. If you replace the seat you still have to take the old one out so if you are going to do this you may as well try to repair the old it depends on how handy your are I suppose. Once you can get to the switch which is only small about the size of a 2p piece you can see the wires leading up to it. In my case the repair cost me nothing as it was just a case of adding in a bit of new wire and soldering

 

[Craiglxviii]

This is a very good point and to which I say, you're absolutely right, you just don't know. If you can repair it (I couldn't see the switches on mine so didn't bother) on yours I'd be really interested on some photos and any repair you try to do.

If pushed I'd hazard a guess at the microswitch itself going a china, I do not know how easy it would be to source a replacement part.

 

[television]

I have been looking at the circuit, not easy to work out but the culprit could be the hibernation S92 switch

 

[cl500 probs]

Same Issue

Hello Everyone,

Similar problem here, message on dashboard saying passenger seat backrest unlocked, Despite being able to move the seat, backrest and everything else.

After reading any forums available on this issue, i located the sensor and started to look at the wiring. Looking at the wire it seemed like at one point they looked bent and exposed.

First think i did was check to see if any power coming through, checked before and after the bend and nothing. Regardless i got extra wire and soldered the wires and hooked everything up. Still no power. (i removed the battery and put it back on to see if a that kinda of reset would work)

I have removed the seat now and looked at the wiring further and don't see anything out there.

Please help out.

What should i do next.

 

[television]

Could the fault be that hibernation switch module.

 

[Craiglxviii]

Hello Everyone,

Similar problem here, message on dashboard saying passenger seat backrest unlocked, Despite being able to move the seat, backrest and everything else.

After reading any forums available on this issue, i located the sensor and started to look at the wiring. Looking at the wire it seemed like at one point they looked bent and exposed.

First think i did was check to see if any power coming through, checked before and after the bend and nothing. Regardless i got extra wire and soldered the wires and hooked everything up. Still no power. (i removed the battery and put it back on to see if a that kinda of reset would work)

I have removed the seat now and looked at the wiring further and don't see anything out there.

Please help out.

What should i do next.

I wouldn't have removed the battery- that could cause further problems!

Where on the seat harness did you go to? There are two connections, the main seat actuator (front/ back movement) and the <backrest tilt/ headrest up/down and anti-submarining ramp front/back> actuators. I do not know to which bundle the lock/ unlock microswitch wiring is plumbed into but I presume that it goes into the CANBUS, which means that the signal is carried by the wiring "ring main".

For the seat to move it has to draw some fairly hefty current so I doubt that the main actuator wiring would be dead, it's going to be manly stuff- and as you say, this isn't the case. The car won't self-test without the ignition on to position #1; you MUST NOT put the key in the ignition with the seat disconnected or the SRS will detect a fault, come on and you will have to have the car plugged into STAR to reset it.

How did you test the wiring, using a resistance test with the seat removed (and ignition off)?

 

[cl500 probs]

Before i removed the seat or any wiring, i disconnected the battery for awhile then plugged it back on. NOW before removing the seat i disconnected the battery and have left it that way.

Testing for current/power, i did this in the beginning when the seat was in place and battery was hooked up. i used what i think is called a circuit wire tester. Basically the one that looks like a screwdriver with a needle tip, that has light bulb and a wire you connect to any conducting metal.

Regarding the switch connector, i believe you right, if i understand correctly. I am currently at work, when i get home i will take a few pictures and upload them.

Thank you

 

[Craiglxviii]

Just be ever so careful on connecting and disconnecting the battery. The cars do not like it and I believe the CL is worse than most with maybe the exception of the SL! They like a constant, steady availability of power. To give you some idea, my car had had a flat battery when I bought it, was jump started 3 times, and I cleared off I think 138 separate fault codes all to do with impermissible voltages or implausible sensor readings when I first bought my code scanner...

I'm really not familiar with the whole CANBUS setup to be able to advise on continuity testing, Malcolm here is your best bet. Would need to trace where the microswitch wiring goes to in order to work out what's knacked.

I'm not a betting man (if I was I'd have been in a Leicester bookies 8 months ago!) but I'd take a punt on you replacing that seat with one from a scrapper..........

 

[television]

As far as I could see in the wiring diagrams that little box at the top did not go anywhere else.

 

[Craiglxviii]

So either it's a main harness fault... or the OP hasn't tested the extended switch harness properly... or we're missing something.

Maybe the cable that carries the CANBUS signal has enough impedance somewhere to lower that signal below where the seat/ SRS ECU can read it?

 

[Roadtoad]

The electronics on these cars can be a nightmare. One of the first things I did when I bought my CL was to get myself a Star Machine. Best investment I ever made. Once you get the hang of it you can hack into the electronics of the car and test them. So for example the seats you can move them remotely from the laptop. If there is a problem it will tell you where it is and then once you have identified the dodgy part you can bring up another menu which will show you where the part is located on the car.

 

[cl500 probs]

Just be ever so careful on connecting and disconnecting the battery. The cars do not like it and I believe the CL is worse than most with maybe the exception of the SL! They like a constant, steady availability of power. To give you some idea, my car had had a flat battery when I bought it, was jump started 3 times, and I cleared off I think 138 separate fault codes all to do with impermissible voltages or implausible sensor readings when I first bought my code scanner...

I'm really not familiar with the whole CANBUS setup to be able to advise on continuity testing, Malcolm here is your best bet. Would need to trace where the microswitch wiring goes to in order to work out what's knacked.

I'm not a betting man (if I was I'd have been in a Leicester bookies 8 months ago!) but I'd take a punt on you replacing that seat with one from a scrapper..........

FUTBALL: LOL leicester ..... simply unbelievable

CAR : Your saying to buy a seat from the junk yard? I don't know if it would be worth it. Any way to get the message off?

A distant friend has the STAR system, any way that could help ?

 

[cl500 probs]

The electronics on these cars can be a nightmare. One of the first things I did when I bought my CL was to get myself a Star Machine. Best investment I ever made. Once you get the hang of it you can hack into the electronics of the car and test them. So for example the seats you can move them remotely from the laptop. If there is a problem it will tell you where it is and then once you have identified the dodgy part you can bring up another menu which will show you where the part is located on the car.

I have a apple laptop, i dont think its possible to hook it up, or else id buy one.

 

[Roadtoad]

Mine runs on a Dell D630 which I bought cheap on Ebay (other auction sites may be available) I bought the multiplexer + software pre loaded on another hard disk from supplier in China then just swapped hard drives. Another cause of your problem could be something jamming the mechanism. Pens are a favourite that slip down the seat check this before you do anything that involves spending money from your childrens inheritance

 

[cl500 probs]

I still need help

I apologize for this late response.

I have attached the two photos to this response. Nothing was jammed there i was able to press it all the way down and visually inspected it as well.

Let me know if the pics help. Second pic is of the sensor and the first is where the wire ends up connecting to.

 

[Roadtoad]

In your 2nd picture you can see the microswitch attached to its mounting plate. First of all check to see if the switch is still physically working. Is it clicking ? If so check the wiring up to it. I can see that it has been repaired before but it looks like the what was the brown wire is now connected to the blue from the microswitch. I wonder if this is the problem ? You could check the connection where its been taped up and swap the ends around while you have it dismantled.

 

[Craiglxviii]

FUTBALL: LOL leicester ..... simply unbelievable

CAR : Your saying to buy a seat from the junk yard? I don't know if it would be worth it. Any way to get the message off?

A distant friend has the STAR system, any way that could help ?

Yes that is exactly what I'm saying. I did- I actually had a slightly rattly mechanical lock on my driver's seat- and a replacement part from a breaker sorted me out fine, no problem at all. Some slight scuffing to the leather (bolster) was sorted out with black spray paint (for leather!) colour matched to CL500 black. Total cost, £120 for the seat delivered and £25 for the leather spray- which I then ended up using on steering wheels of my other cars

 

[cl500 probs]

In your 2nd picture you can see the microswitch attached to its mounting plate. First of all check to see if the switch is still physically working. Is it clicking ? If so check the wiring up to it. I can see that it has been repaired before but it looks like the what was the brown wire is now connected to the blue from the microswitch. I wonder if this is the problem ? You could check the connection where its been taped up and swap the ends around while you have it dismantled.

The switch still clicks, does this mean the switch is not at fault?

The repair was done by me and my dad. Initially the wires looked broken at that spot so me and my dad cut the wire and soldered a piece to extend it. We used what ever wire we found so the wiring colors are not consistent with the original colors however the colors pre repair are consistent with the ports.

 

[Roadtoad]

You could easily test the switch now its off with a circuit tester as its just an on or off switch but if its clicking I suspect it will be ok. Your previous repair with the wire is exactly where mine had worn through. Are you sure about the blue to blue ? Im following it through on your pic and it still looks to me like the blue is going to brown. Is this the switch thats from under the seat base or the one on the side of the seat for the backrest, as both come into play with the auto forward action.

 

[television]

Micro switches will always click, but they must be tested with an ohmmeter, when there is no connectivity I have always fixed them by washing out with lighter fuel. this has to be poured in to the little button while depressed, not the lever. One can follow up with switch cleaner.