[Kajtek1]

Can someone come up with a test procedure for wires?

$3 tool

 

[MRBSMITH]

And it just keeps on going

I am sooooo proud of you all.
Keep em running
B

 

[MrGadget608]

SRS Light, Passenger Seat Occupancy Sensor - Broken Wire - Fixed

Kudos to the forum ... again. Found & fixed the broken brown wire to the Passenger Seat Occupancy Sensor. It was broken inside the insulation with no sign of wear or scraping. It was broken about an inch from the under-seat computer module, so we had to remove the entire seat cover to get to it.

The only thing I might add (beyond what's already in this thread) ... after repairing the broken wire, but before putting the seat back in the car, we reconnected the sensor to it's wiring harness to see whether the light went out. It didn't ... but that's because the Seat Belt wire was still disconnected (Doh!).

BTW - We verified the problem with a local MB Indie before starting the repair. The code was "B1315-003: Front passenger seat occupied and child seat recognition (B48), or the signal has an open or short to power".

Thanks for helping us saving hundreds of dollars for a simple repair.

 

[awuanrap]

I have a 2005 C-320 with the SRS light on. I realize my car is a W203, but this thread seemed applicable to my problem, so I read this entire thread. I have an icarsoft i980 scanner, and I get three codes under air bag, 907C, 907D and 907E. Can anyone tell me if these codes point to the seat weight sensor, or, if not, what they do point to? Thanks

 

[awuanrap]

Well, I found my problem. A lot of people in this thread said their problem turned out to be a broken wire between the cable interface under the seat and the sensor mat/module itself. These wires were solid copper, and broke with flexing or a vibration. I figured this might be my problem too, so I pulled the seat out to check the wires. Once I got the seat upside down on my bench, I saw that the connector that plugs into the weight sensing system (WSS) module itself had come out. Note, this is not the yellow plug to the cable that comes out from under the floor mat, but the connector into the WSS module itself, which is back much further under the seat, and up higher, more under the seat cushion, which is why I couldn't see it until I got the seat out and upside down on the bench. I plugged the cable back in, and put a tie wrap around it so it wouldn't come out again. I re-installed the seat, cleared the trouble codes, started the car, and no SRS light.

 

[9ninsix]

Anyone in the los angeles or orange county area familiar with the procedure willing to help with this fix for a fee? I barely was able to help my son put together his lego set and have been putting off this repair.

 

[MRBSMITH]

omg it cant still be relevant after all these years?
B

 

[Mysticmal]

Great post with many views. Nothing for 12 months so everybody must have fixed their passenger sensors
I now have the srs light on, was intermittent but then hard on.
suspected it was the passenger sensor,but before hacking into wire I got the codes read. Indy had a snap-on reader.
result: Airbag 9025 : component B48(front passenger seat occupied and child seat recognition) faulty.
Car is A209 clk cabriolet, 2008 build, and a few differences to the photos. Australian car.
Has heated and pneumatic multi-form seats. All the complications!

Was Hoping to be lucky and only have to fix broken wire.
Checked continuity of red,brown,white wires up to where they disappeared into seat using ohm on multimeter. All ok.
Dismantled seat enough to get the box for the pressure pad exposed, with the intention of flipping its lid and doing full end to end continuity. HA!, foiled again! Box seems to be filled completely with hard plastic, so can’t get to the internal end of the wires.

While re-testing continuity, I noticed that there was some connectivity between the pins on the plug itself. Some resistance but NOT open circuit.
QUESTION: does this mean that the wires are all actually intact and not the problem as they allow current flow to the pad and back?
for those with a bit more electrical nouse than I, does it seem ok that the circuit is closed (with resistance) when the pad has no weight on it? Ie what is normal for a working pad?
If this is the type that transmits pulses (ie not variable resistance type) what should be seen?

ALSO: the control levers for the seat pneumatics are attached to the side of the seat with POP RIVETS. And.... the rivets go thru the seat cover making it impossible to remove. Is this normal? See two pop rivets in photo.

Help appreciated.

 

[mrboca]

If this is the type that transmits pulses (ie not variable resistance type) what should be seen?

Pulses.

For W210's, the communication between the seat pad and the SRS controller is based on pulse coded signaling. For A208, I do not know, but very likely it is pulse coded too.

 

[tabijan]

Can’t you drill out the rivets then pop new rivets after you’ve repaired the sensor?

I’d like to retrofit bolsters to my seats but in a 210 the control pod brackets are welded to the seat frame in a way I can’t remove them at the wrecking yard.

Sixto
98 E320 wagon 198K miles

 

[Mysticmal]

Thanks.
yes I will drill the rivets if necessary. Just showing surprise that the seat cover has essentially been riveted in! a couple of torq screws would have been nice..

Any thoughts on the question of seeing some continuity between the plug pins? Is this expected if it is a pulse signal from the pad? Eg should I be seeing open circuit between pins? Battery is disconnected btw.

 

[Mysticmal]

SRS Dixie. Ie. Gone away.

I put it all back together and the srs light is behaving normally. A couple of weeks now.

Did not find out what was wrong though. Here is the main sequence.......

1. Started to get intermittent srs light. No passenger. For at least a year. Eventually it stayed on.
2. jiggled wires under seat but usually no change. One time it did go off after Jiggling.
3. decided to fix, got codes read. $55. Pointed to passenger detection pad.
4. hoped it was a faulty wire but had to remove seat to get at it.
5. tested wire for continuity to where it disappeared into the seat. Exposed inner wires, stuck a pin through each and got continuity to connector pins. No problem there. Pulling,bending wires made no change.
6. Decided to test at control box. Managed to access box by pulling just the front of the seat pad back.
7. tried to open control box but found it was filled with solid plastic!!! So could not do end to end testing.
8. decided to check if the problem still existed.
9. Placed seat back in car; seat cover still partly off. Not bolted down yet.
10. Hooked up all the connectors and pneumatic feed to seat bladders. Ensured connectors were clean. Reconnected battery.
11. Started car, and no SRS light. (Came on for 5 secs then off, as required. )
12. Jiggled all the wires to see if problem came back, but no (not yet anyway).
13. So, removed seat, stretched cover back on, plus various cover plates etc. replaced in car; connected up; started car to show no problem; bolted seat down.

So, it is fixed. I just don’t know what was wrong.
Getting the pad replaced would have cost at least $750 Australian. Glad I didn’t jump straight in. So far cost has bee $55 and my time.

It may come back of course, but at least I now know how to pull out seat,disconnect and remove cover. Thanks Benzworld members .

I did make sure that the underseat wiring straps were not as tight as before, to lessen the risk of them breaking under tension, or pulling the connectors. They were pretty tight.

I will report back if anything changes.

 

[Montazerir]

do you have any tips on how to check seatbelt switch , or seatbelt tensioner causing the SRS get illuminated on driver seat

 

[mrboca]

do you have any tips on how to check seatbelt switch , or seatbelt tensioner causing the SRS get illuminated on driver seat

Please provide the model and model year of your car first as hardware can be different from year to year.

 

[patkana1]

Next pics

Here are the next set of pictures.

Thank you for the Post, It Helped Me out a Lot, I replaced my seat bottom cushin and back!

 

[caleno69]

Con el cable roto, a ustedes les ocurria que ¿cuando alguien se sentaba en el puesto del pasajero, el testigo SRS se apagaba? O el testigo permanecia siempre encendido aún con alguien sentado.
Revisa primero los cables

Las luces de mi SRS y la bolsa de aire del asiento del pasajero se encendieron hace unos días, así que seguí las excelentes instrucciones en este hilo para quitar la almohadilla del sensor. Antes de asumir que la almohadilla estaba defectuosa, pensé que valía la pena inspeccionar los cables.

Visualmente, los cables se veían bien, sin rozaduras ni cortes en el aislamiento. Quité el aislamiento exterior para revelar los 3 cables individuales que también se veían bien. Como verificación final, quité el aislamiento de cada cable, cerré la "caja" y verifiqué la continuidad desde ese punto hasta el enchufe amarillo. Efectivamente, un cable se rompió dentro del aislamiento incluso sin señales de daño desde el exterior.

Cuando mi ohmímetro no mostró resistencia en el cable blanco, tiré ligeramente de cada extremo y se partió por la mitad. Un empalme rápido y todo está bien. La mejor parte es que me costó nada más que unas pocas horas de tiempo.

Si tuviera que hacerlo de nuevo, probaría los cables antes de separar la almohadilla del asiento (clips de plástico blanco), ya que la parte más difícil del trabajo fue lograr que esos clips se engancharan en los cables cosidos dentro del asiento.

Espero que esto ayude a alguien a evitar el gasto de reemplazar un sensor perfectamente bueno.
[/CITA]

 

[caleno69]

Con el cable roto, a ustedes les ocurria que ¿cuando alguien se sentaba en el puesto del pasajero, el testigo SRS se apagaba? O el testigo permanecia siempre encendido aún con alguien sentado.
Revisa primero los cables

Las luces de mi SRS y la bolsa de aire del asiento del pasajero se encendieron hace unos días, así que seguí las excelentes instrucciones en este hilo para quitar la almohadilla del sensor. Antes de asumir que la almohadilla estaba defectuosa, pensé que valía la pena inspeccionar los cables.

Visualmente, los cables se veían bien, sin rozaduras ni cortes en el aislamiento. Quité el aislamiento exterior para revelar los 3 cables individuales que también se veían bien. Como verificación final, quité el aislamiento de cada cable, cerré la "caja" y verifiqué la continuidad desde ese punto hasta el enchufe amarillo. Efectivamente, un cable se rompió dentro del aislamiento incluso sin señales de daño desde el exterior.

Cuando mi ohmímetro no mostró resistencia en el cable blanco, tiré ligeramente de cada extremo y se partió por la mitad. Un empalme rápido y todo está bien. La mejor parte es que me costó nada más que unas pocas horas de tiempo.

Si tuviera que hacerlo de nuevo, probaría los cables antes de separar la almohadilla del asiento (clips de plástico blanco), ya que la parte más difícil del trabajo fue lograr que esos clips se engancharan en los cables cosidos dentro del asiento.

Espero que esto ayude a alguien a evitar el gasto de reemplazar un sensor perfectamente bueno.
[/CITA]

Check the wires first

My SRS and passenger seat airbag lights came on a few days ago so I followed the excellent instructions in this thread to remove the sensor pad. Before assuming the pad was faulty I thought it was worth the time to inspect the wires.

Visually the wires looked fine, no chaffing or cuts in the insulation. I stripped off the outer insulation to reveal the 3 individual wires which also looked fine. As a final check I stripped back the insulation on each wire close the "box" and checked continuity from that point to the yellow plug. Sure enough, one wire was broken inside the insulation even with no sign of damage from the outside.

When my ohm meter showed no resistance on the white wire I lightly pulled on it from each end and it snapped in half. A quick splice and all is fine. The best part is it cost me nothing but a few hours of time.

If I had to do it again I would test the wires before separating the seat pad (white plastic clips) as the hardest part of the job was getting those clips to catch on the wires sewn inside the seat.

I hope this helps someone avoid the expense of replacing a perfectly good sensor.

 

[caleno69]

With the cable broken, did it happen to you that when someone sat in the passenger seat, the SRS warning light went off? Or the warning light always remained on even with someone seated.