Hades,

To me, it sounds like the battery connector on your switch harness was the culprit.

It may be a good idea to replace it anyway.

If you insist on using the old switch harness, here's something you can do to to verify that it's at least good for some flights...

Connect the battery, Switch to off, connect voltmeter. You should get a good reading. Now, move around the battery connection to the swtich harness. If it's good, the voltage reading on your voltmeter won't change. If it changes, then perhaps some of the wires in the switch harness connector are broken. If so, CHANGE IT. This will be an accident waiting to happen.