300E electrical mystery

[John Hockin]

My 300e has exhibited strange elecrtical, behaviour for the last 4 years. After 2-6 hours on the highway in the summer the SRS light starts to flash irregularily. Eventually it has actually come on and stayed on. during this period if i come off a ramp and stop the electrics will often fail completey and the car dies at about 40KPH. The car has always restarted right away.
This happens only in the summer when the engine room is hot. BUT the electrics have also often failed when i slow down at other times in the year in city traffic, when the SRS light is not on. Some times this can happen three times a day and then not reoccur for months.
I believe the car was in an accident ( pass side) before i had it and think maybe it is related to this.
My mechanic ( excellent) has never been able to find the problem nor has anyone else i have ever discussed this with.
Any idaes out there??????