Car randomly cuts out (electrical fault)

[Merc30]

So I'm cruising on the motorway and all electrics fail, car shuts down instantly.

I get out, loosen the battery terminals and wiggle them about. The car starts up again.

This has been happening on and off for weeks. So as I was wiggling the terminals one day, I noticed sparking from the earthing lead fixed to the inside of the wing. I replaced it and everything was fine for a few days, but the car went dead the other day again.

A few days ago I was working on the car on an unrelated issue, closed the bonnet and went to lock the car but noticed the central locking wasn't working. The electrics had died by the action of closing the bonnet. I've checked all the connections are tight and solid. So what's the deal?

2.5 16v '89 I'm thinking of giving up on this car. Got other probs too.

http://www.mbclub.co.uk/forums/engine/129522-2-5-16v-auto-gearbox-acceleration-prob.html

 

[grober]

Sounds as if you have a problem with the fuses/fuse holders in the main fuse box. This type of fuse can corrode where they clip into the holders giving weird intermittent electrical problems. [ WELL KNOWN PROBLEM] I suggest after disconnecting the battery taking out each fuse individually and cleaning the fuse and fuse holder contacts before replacing . Fine plain nylon type pan scourers[ not soaped ones] are good as they leave non conducting fragments. Check the engine earthing strap connections at the same time. Remember also that all earth straps can have internal breaks /corrosion which may be covered by their insulation and not obvious to casual inspection.