SRS RED light on 560SEL 1989 - PeachParts Mercedes-Benz Forum

zcc · #1 12-08-2005, 01:26 PM

I bought this car with this problem; the SRS red light remains lighting as long as the engine is started.

It's diuble air-bag. I did my best to fix it but no use.

I discovered something; i know that to fuction properly when I turn the switch a little bit before I start the engine that the light will turn on for some seconds the off. With my car it turns on and after a few seconds it blinks but barely noticed blinks. And this blink remain until I turn off the engine.

Please I really need to know how to fix this problem. I went to the best electricals but all said that there is no computer wiring to fix your car because it's 1989.

Thank you in advanced : ))..

Two560Two · #2 12-08-2005, 01:48 PM

The airbag module is in the center dash right under the ashtray and radio. Take the ashtray out and you will see an Airbag module or computer. Take it out and replaced with another. If problem still persists then its either in the airbag computer or your electricals. AS ALWAYS- Disconnect the battery when removing that airbag module and when installing one

zcc · #3 12-08-2005, 02:22 PM

Great, I will do it next week and see : ))..

Thank you from the information.

MikeTangas · #4 12-08-2005, 09:12 PM

Actually, I don't beleive you can see it through the ashtray opening. IIRC the crash sensor is under the insulation mat. You have to pull the center console and lift the mat. The sensor is attached to the tranny hump with 4 screws.

The SRS MIL could be lit due to a faulty or disconnected airbag, faulty or disconnected ETR (seat belt tensioner) or a tripped crash sensor ie: the car was in a wreck and the blown bags were replaced and not the sensor. Same would/could happen if the bags and sensor were replaced but not the ETR's.

lkchris · #5 12-09-2005, 12:23 AM

On w124s at least, this light most often indicates simply faulty brushes in the steering wheel, i.e. nothing really wrong with the airbags but rather just the wiring in the steering wheel.

glenmore · #6 12-09-2005, 11:45 AM

Quote:

Originally Posted by lkchris

On w124s at least, this light most often indicates simply faulty brushes in the steering wheel, i.e. nothing really wrong with the airbags but rather just the wiring in the steering wheel.

This was the cause of my SRS light. I checked the easy stuff/cheap stuff first, loose tumbler/ignition, seat belts, voltage regulator, and finally the horn hub behind the steering wheel. About an $80 part. Easy DIY once you get the steering wheel off. If the bolt is in there good, you need two people to break it loose. One to torque and the other person to hold the steering wheel. If you notice the SRS light flickering coincident with turing the steering wheel, this is probably it.

glenmore
1991 300CE
1990 LS400
2000 C280

zcc · #7 12-12-2005, 03:21 AM

Where is the voltage regulator for the SRS on 560SEL 1989? (Double airbag)
And how can I find the loose tumbler/ignition?

The fickering occurs without turing the steering wheel. I opened the steering wheel and all was connected properly and no bad wires.

Thank you : ))..

lkchris · #8 12-12-2005, 11:30 AM

Quote:

Originally Posted by zcc

The fickering occurs without turing the steering wheel. I opened the steering wheel and all was connected properly and no bad wires.

Thank you : ))..

It's brushes that go bad in steering wheel. The items that contact the slip ring as wheel turns. Movement is NOT required to light the SRS light.

zcc · #9 12-12-2005, 11:35 AM

Where is that brushes inside the stearing wheel?
Do you mean the little wire with the red head? If so, can I fix it or I have to change it?

Thanks...

glenmore · #10 12-12-2005, 12:31 PM

This is with a W124, 1991 300CE. Don't know if it is the same with your car.

The air bag is attached with 2 torx bolts and the wire with the red head.

Remove the steering wheel to expose the brushes, little spring loaded contacts. These are cheap to replace. The contact ring is on the underside of the steering wheel. At first I also replaced the SRS module because it was a cheaper part ~$30, but it required removal of the lower dash and going deeper into the steering column. This didn't solve the SRS light. so I broke down and got the horn contact ring ~$80 and this solved the problem. There was nothing visually wrong with the old hub ring.

Voltage regulator is a small module that attaches to the alternator? with 2 screws. It wears over time and causes all sorts of electrical glitches. Easy DIY on my car.

The tumbler/igintion is the thing you stick your key in to start the car. They get loose and sloppy with age. And in the W124 they tend to break leading to the dreaded frozen tumbler. I am not sure how this can affect the SRS light but it was one of the things to check as suggested in other posts.

glenmore
1991 300CE
2000 C280
1990 LS400

zcc · #11 12-12-2005, 02:40 PM

ok guys, I got the information and i'll do my best to get fixed. Thank you so much : ))..

zcc · #12 12-20-2005, 05:15 PM

Still not solved.
I did the followings:

1. Reset the ANALOG error code.
2. Changed the driver's airbag.
3. Checked the brushed and all cleaned.

What else I can do? The car has a double airbag not one.

zcc · #13 12-21-2005, 10:47 AM

Shall I replace the passenger's airbag to test also?