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Discussion Starter #1
Would appreciate any comments on the following. My 2003 SL500 SRS light stays on each morning after start for 15 or 20 minutes. After going off it stays off for the rest of the day (6 to 8 hours) after subsequent starts. No malfunctions noted on vehicle dash display. MB dealer found no error codes and claims that this is common for the model and not a safety issue. Any familiarity with this issue?
 

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It might be your seatbelt. Mine was doing the same thing and i replaced driver side seatbelt and the problem went away.
 

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Discussion Starter #3
What component of the seat belt was the culprit? What was actually replaced? The reason that I ask is that there was a thread a while back which focused on the SRS light but in that case stayed on permanently as opposed to my case where it regularly goes off after about 20 minutes and then stays off the rest of the day. The solutions given previously were, as in your case the seat belt, also the electrical connector under the seat and sensor. The regularity of my light in going off seems to rule out a faulty or high resistance connection. Any thoughts?
 

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He replaced the entire seat belt assembly. It was like 300$ plus labor

Check connections under the seats. Use some kind of contact cleaner to make sure you have good contact.
You say that it goes away after some time. is it the same in warm weather and in cold?
Mine would go away if i pulled on the seat belt a lot. Than restarted the engine.
Or by itself after a while of driving.
 

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Discussion Starter #5
I tried the belt pulling action but it didn't work. Looked under both seats, disconnected the yellow connector and sprayed with a commercial circuit cleaner. Made no difference. Failed to mention two other facts. The first is that if I drive less than about 20 minutes, say 15 minutes, turn off the engine and come back and restart after 5 minutes the light goes off. Again a time related event. The second fact is that the seat belt warning light remains off at all times and no audio alarm is given when not buckled. I was told that the previous owner had it disconnected professionally and no error event code occurs when scanned. Could this influence the curious performance of the SRS light?
 

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as far as i know during start system checks all the components of restraint system. Maybe bypassing seat belt causes the SRS light to go on. Some kind of system glitch.
 

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Discussion Starter #7
I believe that you are correct. If there is a self check going on then 20 minutes represents quite a few clock cycles before the code decides that everything is OK. Again no diagnostic code ever appears as per MB dealer check nor vehicle display. Forgot to mention that the ambient temperature also doesn't seem to make a difference as it has gone from the 90's here in the East to a current 39 this AM. Same 20 minute default cycle prevails. Since it doesn't appear dangerous at the moment I will keep checking and report on any prospective solution. Perhaps someone in the future will have the same problem. Thanks for your help.
 

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I know you said that the computer did not show any error codes. But was it tested with the SRS light on? or after it went off?
It makes a big difference.
If you checked for errors with the SRS light already off than computer would not display any SRS error codes.
I would suggest running the test right after you start the car when the SRS light is still on, That would give you the code for faulty component of the restraint system.

ps
I would put my money on the error being caused by Bypassing your seat belt.
 

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Discussion Starter #9
Thank you to Gary for the steering wheel suggestion. I tried it but it did not work. Funny that you mentioned it as it relates to a S430 (orS340?) that I leased in 2000. It had so many electrical faults that I had MB dealer folks come to my driveway monthly. Got rid of it as soon as the lease expired. In any case they would turn the wheel lock to lock a couple of times each time they worked on my car and encouraged me to also to clear settings.
With regard to the question of whether the dealer checked the error codes with the light on or off, the answer is light off because it takes me 30 minutes (at least) to get to the dealer. The only other possibility would be to leave the car overnight which raises logistic problems for me. I thought that any error code is stored until cleared by the MB techs, not true? I guess the only real danger is whether the SRS is working during that morning 20 minute period. The under seat connectors are connected and do not appear to be tampered with in the seat belt warning system. I'm open to any suggestions. Thanks to all.
 

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Walt
I have the same exact problem but mine only last 3-5 minutes. I will check the wiring diagram to see if I can figure this anomoly out. I have no buzzers associated with my seatbelts but I am unsure if the previous owner did the same thing with the seatbelts your car has. Not sure if the 1995 is the same and has buzzers. Maybe not but this could be the link that explains our symptoms. I will work on it. Let me know if you find anything.
Jesse
 

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Would appreciate any comments on the following. My 2003 SL500 SRS light stays on each morning after start for 15 or 20 minutes. After going off it stays off for the rest of the day (6 to 8 hours) after subsequent starts. No malfunctions noted on vehicle dash display. MB dealer found no error codes and claims that this is common for the model and not a safety issue. Any familiarity with this issue?
I had a 2003 which had same problem. It will get worse to the point it stays on all the time. The issue is the pre-tensioner seatbelt wiring. They have a kit to repair and both seats are to be done. The problem is over time the resistance in the wire goes up.The fix cost me $600 (ripoff as usual) but it worked. Both seats have to be removed. My 07 SL55 AMG is trouble free.
 

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Discussion Starter #13
Is it possible or feasible to just bypass the seat tensioner or will that trigger more problems?
 

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Discussion Starter #14
Fixed at last. I pressured the original dealer (not MB) to fix the SRS problem He sent me to the local MB dealer who worked on the problem for two days. It turned out to be a broken
/open wire in the SRS harness which behaved intermittently. The mechanic just bypassed it and all is well now. No cost to me. Don't know if the extended warranty would have covered it.
 

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2003 S55K, 2002 W220 S430 (RIP), 1999 W163 ML430, 2004 W230 SL500 Sport
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I don't have this problem yet but when I had a BMW 740i it was the same problem of the SRS light staying on. It had something to do with an open circuit in the seatbelts. On the BMW it was the actual latch and buckle of the seat belt. When you buckle it in. It actually closed the circuit and no SRS light on.
So I would use an ohmmeter and see from the buckle to the latch when fastened if it is an open circuit. Just an idea.
 
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