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  Topic Review (Newest First)
11-28-2018 02:32 PM
Eddieba I thought I was having same issue on my 1995 SL320 but when I took my right seat off, there was no wire or wire or sensor. I went back a couple of years and my mechanic made note of passenger seatbuckle is setting off the SRS.

Does anyone one know about testing the Seatbuckle while I have the seat off? Or a way to bypass the seatbuckle sensor?

I’ve sprayed cleaner and air into it so far.

09-22-2018 04:15 PM
Photodude Of course this helps, Thanks. I had no idea where to start with this.

I actually just installed the seats back, I didn't even realize how much better (firmer) passenger seat was until just now that it is on MY side. Little cleaner too.

At some point though I might replace both cushion pads. So it's good to know.
09-22-2018 03:25 PM
Originally Posted by Photodude View Post
...I'd still be curious how to remove leather from the seats, just in case I wanted to replace cushion pads. What's the trick to get it off?
I've replaced the skin on the bottom of my SL500, it's kinda difficult to explain, but basically, there is a metal channel all around the perimeter of the bottom of the seat. Skins have fiber strips sown in that tucks in those metal channels. To remove, the seat bottom should be in upside down position as you have in the picture, apply firm and even pressure (knee) to the middle of the metal frame, that relieves the tension of the skin and carefully, start pulling the fiber strip from the channel carefully, starting at the back.

Not sure if this helps, but here is someone's blog (early model, but the principle is the same), you can see the fiber strip and the channel fittings R129 500sl Restoration: Reupholstering the 500SL

09-22-2018 12:16 PM
Photodude Something is definitely wrong with the sensor or wiring, doesn't matter really. I like the emulator solution, cheap and easy. This sensor would probably be problematic even if replaced and I don't really need it.

I'd still be curious how to remove leather from the seats, just in case I wanted to replace cushion pads. What's the trick to get it off?
09-22-2018 06:36 AM
ka707 This is what the sensor looks like. Note I pulled the squab out, then the leather cover off the squab, then the sponge seating off the sensor. I have a spare sensor which I bought and in the end did not need it! Before you do all of that check out the condition of the wire leading from the sensor to the plug under the seat. you can see it here in the pic at the very bottom, a grey wire running away from the seat.

Now, when the seat is in place, this wire runs through the metal frame that holds the seat squab in place. The wire flexs ever so slightly as the seat is used. One of the wires had broken inside the grey insulation at the point where it crosses the hole in the metal frame. I found this out after I pulled the whole seat apart unnecessarily. Easy to check continuity with a meter! Hope this helps. COme back with questions if you need to

09-22-2018 06:29 AM
ka707 I might be able to help here, I had the same problem and fixed it easily, it came down to a broken wire. I'll come back with a longer description of the problem
09-22-2018 02:56 AM
Originally Posted by Photodude View Post
Also are driver and passenger seats identical?
Yes, except for later models incorporating the air bag sensor in the passenger side.

Originally Posted by sorayuth View Post
...end up with order emulator from Ireland.
That emulator likely consists simply of two or three resistors and a diode. Together they all cost less than $1.

The diagnostic manual essentially explains how to bypass the sensor here: STAR TekInfo (bottom of page). Across two sensor wires you connect a "1N4007" diode in series with a 300-ohm resistor, and in parallel with that you place either a 30K-ohm or smaller resistor to show the controller the seat is occupied, or a 75K-ohm or larger resistor to show it is not.
09-21-2018 10:04 PM
Originally Posted by e-420 View Post
no seats are not identical, and the drivers and passenger side don't have the same air bag sensor. IIRC the drivers side may not even have one.
I didn't mean identical as far as sensors, Gee I hope they didn't put child sensor on driver side…

I should have said symmetrical… so they would fit on the opposite side. If I were to replace sensor I could fit it on Driver seat and put it on passenger side. Or if I were to use emulator I could just swap them without any additional work.

Just a thought because passenger seat is in better condition.
09-21-2018 08:49 PM
Originally Posted by Photodude View Post
OK. I didn't realize how easy it is to take this out…

Now, I've never done upholstery work so how do I get the leather off. Is the sensor pad a separate part or integrated into seat cushion?

Also are driver and passenger seats identical? I wouldn't mind swapping them.
no seats are not identical, and the drivers and passenger side don't have the same air bag sensor. IIRC the drivers side may not even have one.

try plugging the yellow plug back in and see if the SRS failure goes away. Had that issue on mine once, plug had somehow come loose.
09-21-2018 07:53 PM
sorayuth MY 99 sl500, SRS light on , Air bag light off is on. Check all wirings but all good so the problem is sensor. You can try to dectivate by the switch on the side of the passenger seat (didn't help on mine). Can't find the part on line and have no time to go to dealer end up with order emulator from Ireland. all lights is off. I don't have kid and won't put kid in car anyways. For me, If you don't put kid in the front seat, this is the cheaper and easier way than replace the sensor.
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