I have a 68 mustang with a '72 C4, the neutral safety switch came with the tranny. The plug matches my wiring harness but I'm not getting the rear parking lights to come on. Do i need to switch the neutral safety switch to a 68 year switch?
First, check to see whether power is getting to the switch, at the plug, and if it is, check to see whether the switch is sending power back to the plug. If you are, then you need to trace the wiring harness to the rear, to find the problem.
I just replaced the entire rear harness wiring so I ruled that one out. I think the question i was trying ot get answered was about the compatibility of a switch from a '70+ C4 to a '68 wiring harness, the plugs are the same but the mustang vendors sell them as two different parts. one fits years 1967-1969, the other fits years 1970-1973. Are they installed differently? on my c4 the switch is on the upper side of the shift linkage.