The same relay on our '93 400E began acting up over about a 4 month period and one day just finally died. We made the replacement and all has been fine since.
Since you have an issue with the relay being loose follow Ashman's advice and swap it out if you can. That is what we did before getting the replacement just to make sure we were replacing the correct part. (that's one of the benefits of having two cars with "some" of the same parts!)
Joint Owner of:
'93 400E (80k miles)
- Smoke Silver/Parchment
'93 300CE Cabriolet (43K miles)