1988 560SEL SRS Intermittent Problem

Turn the engine on - SRS light comes on when you start the car and after a couple of seconds goes out. Normal. Drive the car for up to 2 hours - no problem. Take the car on a long trip and after about 2 hours the SRS light flashes on for a second or two and goes out. About 5-10 minutes later it will flash on for a little longer and keep doing this and staying on longer each time until after about 4 hours of driving - it is on constantly. While it is on, while driving, I have tried undoing and re-buckling up the two front seat seat belts. It makes no difference as to whether the light comes on or not. I have tried moving the steering wheel back and forth and pushing and pulling on it while driving to see if it will cause the light to go on and off - it makes no difference. I was trying to see if the seat belt connector or the brass ring in the steering wheel was at fault. Anyone else have this problem or any insights has to what I should try? Spring is coming and I want to get the car out of winter storage in about a month and this is one of the last aggrevating problems I have left on it. Not major but annoying while you cruise on a nice summer day. Outside or cabin temperature has no effect on the symptoms.
Thanks in advance for any insight
Morris

[porkface]

replace the overvoltage relay and cross your fingers. my money's on that. good luck, chuck.

[Paulwho]

moedip,
With the early carbon type SRS brushes the residue will accumulate in the contact plate area causing intermittant flashing of the SRS light. Code three = contact brushes ignition circuit drivers side. The longer the drive on the highway the more likely this will occur. A brisk blast of air at the joint between the steering wheel and column may produce a puff of black residue. Good luck.

Paulwho - thank you for the tip - makes sense - I will try it and post back.
Many thanks
Morris
PS re- code 3 -I have never pulled a code on this car. How do you do it? Will the code only appear while the SRS is acting up or will it be stored?
Thanks in advance.

[Paulwho]

moedip,
Ignition on, ground pin 6 of x92 (the black muti pin test connector near the battery) for 3 seconds. Have someone observe the SRS light and count the flashes. Repeat procedure until the original number of flashes repeats. You may have several codes. After the first code repeats you may now begin the erasure process. Ground pin 6 for 7 seconds, wait 3 seconds and ground pin 6 for 3 seconds. The next code should then flash. Repeat again and again until 1 flash =no codes. Sounds complicated but its not after a little practice. Bibo ergo sum.

Thank you - Paulwho
Now if I may be so bold as to ask one more favor. Where can I find out how many codes there are and what each means? I am sure this info will be very valuable to any 560sel owner in troubleshooting codes. I have been scanning this site for 2 years and have never seen this info
Thanks again
Morris

[Paulwho]

Fault codes from 9/87 w126


Impulse Fault Display

1 No fault
2 Control unit
3 Drivers airbag circuit
4 Front passenger side airbag
5 Drivers seat belt lock circuit
6 Front passenger belt lock circuit
7 Resistor front passenger seat
8 Low voltage, grounds
9 Control lamp, cluster circuit
10 Control unit, very bad code will not erase

Thanks Paulwho - really appreciate this info.
Morris