On Wed, 3 Jun 2015 19:44:16 +0100, News wrote:

I tinned all the bare ends, then joined with two choccy blocks,

Solder might not have been a good idea. It prevents the screw
gripping the wires properly then flows under the presure, loosening
the joint. The vibration in a car I can imagine hastening the
process. The proper thing to use on stranded wires into screw
terminals is plain crimp ferrules.

Having said the joints become poor I've never had a problem with
(old) screw terminals and solder but have found them rather loose.


--
Cheers
Dave.