There is a school of thought that the best thing to do with the ballast resistor is to do away with it but having said I've never had a problem with the one fitted to my 1972 4/4.
I think you've probably identified the root cause of the breakdown being a loose connection. I've never been a fan of bullet connectors but what can you do other than to carefully check each connection and clean if necessary. I do this as part of my pre MoT spanner check. I use a small glass fibre pencil There was also spate of badly fitting female bullet connectors on the market a few years back which wouldn't grip the bullet and required a pinch with a pair of long nose pliers!
Is the isolator switch in the footwell a later addition? Presumably its cut into the low tension circuit?
Might be worth taking a spare coil, ballast resister and condenser with you though as they take up minimal space!
Arwyn
Last edited by Arwyn Williams; 08/07/18 06:09 PM.
