Strangest thing: SRS light comes on
 

While driving my '88 300ce down the freeway in the heat of the day the SRS light comes on for about 2 to 8 seconds then goes off in 10 to 20 second intervals. It seems to only happen when its hot outside and usually only driving down the freeway.

Would this have anything to to do with a worn out alternator? The only reason I ask is when idling with the headlights on I can see the dash lights and headlights will fade in and out like its not pulling enough amps!

next time this happens switch over two lanes.... if it goes out...it's a worn contact ring behind the steering wheel.

tends to happen when you are on straightaways a lot.... not noticeable in town when you are constantly turning .

for the alternator.... just spend the 20 dollars for new voltage regulator brushes...they screw in and out in 5 minutes.

like I always say.... the "S" stands for "spensive"

Is the contact ring expensive to replace? Could it be done by an amature?

As for the Alternator, how many brushes are there? Is that all there is to it, just R/R the brushes and good as new?

regulator.... you buy the regulator which has the brushes attached to it...no more than 25 dollars. as good as new. When I have bought my 300's (i have owned 3). I did these as routine maintainance the same way i changed out all the fluids. It gives me a baseline

contact ring... yes, an amateur could do it... that's what most of us here are.
I believe you need a long torx screwdriver... do a search for the size of the torx and instructions on how to do it.... i think the ring is about 60 dollars...

some have just cleaned the ring contacts and have had success...

My SRS light always stays on in the SL for approx 1 1/2 minutes after start up, then it goes off until the next time I start the car. WTF ?? It really doesn't bother me too much,,, at least about the same as when the wiper parks on the right side of the car for a few seconds,,, sometimes.

The same thing happened to me also. I found the small lead from the alternator loose. Tightened it up and the problem went away.

This is next up on my list to fix.

Is the contact ring on the back of the wheel, or where the wheel mounts/behind the mount?

I'm gonna try and clean it first and see if my SRS light stops flickering on the freeway.

Same thing here...don't know why it only happens when it's warm outside but every time I begin seeing it I give it a good spray with canned air and it goes away until another speck of dust works it's way in. Electronics grease would probably work well

Are you saying you remove the wheel or just shoot around the wheel with compressed air?

No removal. I just stick the little straw on the end and shoot into the wheel from behind, not "full" power on the can trigger, jus enough to get dust and stuff out. First time I did it a nice little cloud of dust shot right in my face :( . Obviously it's not a proper fix but the area of loss of contact in my steering wheel is literally about 1/8" of a turn, for some reason I always hit it perfect when I parallel park on my street. I imagine others with this problem are probably encountering it far more often and throughout more of the wheel's travel/contact

Heck, I'll give it a try and report back in a few days to see if it made any difference!
Thanks!

It's cheap enough to try, it really depends if it's dust and dirt that gets caught or if the contact plate itself is worn through

I've had it since I bought the car back at 66k miles, but it only happened when driving long distances between states. Now in AZ (hot climate coincidence or not...) most freeway driving over 15mins flicks it on and off until I move the wheel.

Roads here are more "straight" than California too, so who knows.

I'm looking for an excuse to upgrade the stock wheel to a leather one anyway. Maybe this it :)

I changed the hub ring out and it solved my intermittent SRS light. I took the steering wheel out a couple of times and cleaned the hub and the light went out for awhile but came back.

It is an expensive part and it may or may not be the cause. I first bought new brushes (cheap) but they did not solve the problem.

Other causes that I have read about are crap in your seat belt buckle and failing alternator.

Two difficulties, 1) a little nerve wracking working around the air bag and 2) getting the steering wheel off. Other than that just a routine take apart, replace and put back together.