Still intermittent "SRS light
 

On my 1990 300E my SRS light comes on and goes off while I'm driving on the highway.Some one told me it was the over voltage protection relay,I changed that,but still get the intermittent SRS light....Can any Help?

it sounds like the clock spring in the steering wheel they wear and short out, not cheap to replace

Possibility the brushes in the bottom of your alternator are worn down. When this happens, the SRS light can come on.

Lots of info on this in the archives - use the SEARCH button.

Seat
 

I have seen my SRS light come-on when I'm getting in and out of my seat. I'm not sure, but there may be a switch in the seat too.

Several times, when an " SRS " light comes on, I have heard of the seatbelt buckles being involved.
In some cases a thorough cleaning ( compressed air ), seems to have been the fix.

Check the voltage regulator first (cheap and easy). But I think you would have other electrical gremlins as well if this was the problem.

Check the seat belts (crud in the receptacle). Not likely but easy and cheap to check.

Most likely though are the SRS brushes that contact the horn hub in the steering column. Should be lots under a search. Brushes are cheap but the horn hub is about $80. You may notice that the intermittent SRS light is coincident with turning the steering wheel.

glenmore
1991 300CE
1990 LS400

The SRS is not on the OVP circuit, it is on its own circuit. OVP will have no effect on the SRS. Intermittent SRS MIL, while turning the wheel can likely be stuck contact brushes or worn slip rings.