My '96 E300 did the same red/green flashing mirror lights and it definately was the K40 relay. Forget trying to solder the connectors and just buy a factory-new one!

I've resoldered every joint about a month ago now and all is still well but I ordered a new one for the winter time - I don't want to be caught in a situation where I loose the engine on a slippery road. It's around $100 from Phil.