wondering if this is a bad switch, just bad connection? light works when switch at the light is changed to the on position

It it the original light?

The newer cheaper ones only work with the switch because it came only with two connections instead of three that came with original light?

the one i have is not original, that was broken and has been discarded- i did not know at the time they were rare- but the one i have does have the 3 connectors, yes

Door switch isn't making a "ground" connection. The spring loaded switch has a couple of pointed pieces of copper that touch the chassis when the door opens - if there is rust at the points where they touch the circuit won't complete. I scratched the rust off the inside somehow (can't remember - curved dental pick maybe) and it fixed the issue.