Can anyone tell me which terminal is which on the back of this 83 TC fog light switch ?
Here is a diagram from the 84 EVTM. With your OHM meter, you should be able to figure out which is which.
Thanks , that sends me in the right direction ... now time for me to obtain an ohm meter :)
86-88 is like this:

...dunno if the 83-84 is the same
Well I can enthusiastically inform you that ..YES 83/84 is the same ... Thank you very much sir