Hi all,I'm having trouble with my parking lights staying on with the headlight switch off,on my '73 C3.I thought it might be the headlight switch so I changed that out.No difference,front and rear parking lights still stay on.I know I have some wires touching somewhere.Just wondering if anybody else had a similar problem.Thanks for any help!This is a small block coupe!

 

The front and rear park lights are powered by a brown wire and both of them are connected together at the headlight switch. If the switch isn't faulty then one of those wires would have to be getting power somewhere else, which is no an easy thing to do really, (as opposed to have one accidentally grounded by a screw or pinched wire somewhere which is pretty easy to happen)
Knowing how hard it is to get at the switch I think I'd try something else first. On the 73 is it possible to reach up from underneath and unplug the headlight switch (on my 72 it's pretty much impossible but there's a couple of extra vacuum lines there too)

Pull the fuse to make sure it's not some other circuit powering them (short)
Pull the bulbs out of the sockets for the front and front side park lights and see if that lets the rears turn off. If it does then the problem is with the front lights instead of the wires and I'd guess a bad ground on one of them, you could put in the lights on one side or the fronts or the sides to narrow it down more.
If the rears stay on, pull the bulbs in the rear (PIA I know) and see if the fronts work ok

Other than that it's looking like it must be the headlight switch, new and faulty parts aren't as uncommon as you'd hope
M

 

It could have been intentional. In my 80, I feed IGN "ON" power into the forward brown wires (ahead of a diode, so fronts only). With white/amber LED switchbacks, this gives me DRLs. So, perhaps a PO did something similar on purpose.

Start ringing out the circuit. I had to use my phone's camera to find the "brown" wire (the third one down).