My running lights and brake lights don't work on
my 1994 chevy s10 if u use a jump wire they will
work but when u put the switch back in and it is
new they won't work
I would test the switch with a volt ohm meter, you know which wires turn on the lights by a jumper, so test those 2 terminals on the switch to see if it makes a circuit. Either the new switch is bad or your wires are not making contact on the switch.
Your hazard switch wouldn't happen to be broke would it?
Search Chevrolet S-10 Questions
Are you a UK consumer? CarGurus now has a discussion forum in the UK.
Chevrolet S-10 Experts