I have a 1996 Ford Contour, and the headlight switch keeps going bad (looks like it’s burned out when I replace it). This is now the third one I’m installing. What would make the headlight switch keep burning out?
- The switches suffer from a poor design or lousy assembly and so are prone to fail.
B) More power is being consumed than the switch was designed for supplying. Aftermarket headlamps or a chafed wire are two possibilities.
III) Bad karma 
Have you checked to see if the connector to the new switch has a bad terminal contact in the connector? A faulty contact there could damage the new switch.
As the previous poster stated the problem may also be due to something drawing excessive current. Check the wires going to the damaged contacts and see where they lead to. Get a service manual if you have to. The headlights should have a relay to handle the high current for them so the problem may be on the running lights circuit.
This car could be carrying the full headlight power through the switch. If it is, seriously consider adding a relay to the circuit. The headlights will be brighter too! Follow the advice of others to check the connections, etc, as well.
What are the exact symptoms and just how sure are you the switch is bad?
After looking over a wiring diagram, it appears the current load(amount of electricity basically) for the headlights is routed through both a low and a high beam headlight relay.
This means the current flow does NOT go through the switch at all. The only current going through the switch is the amount used to trigger the relays, which is near nothing and will not burn anything out.
The only additional current going through the switch is what is used for the dash lighting and the running lights. This is all fused (7.5 amp) on 3 separate circuits - left side lighting, right side lighting, and dash illumination with none of these being a high current user unless there was a short. In the case of short, a 7.5 amp fuse should pop instantly.
Do you have any add-on items on the car such as fog/driving lamps, stereo amps tied into the wrong wire, etc.?
it appears the current load(amount of electricity basically) for the headlights is routed through both a low and a high beam headlight relay.
Unless someone rewired it.
It doesn’t have to be a high current load, just higher than the switch was designed to handle. Everything seems to be marginally designed these days, just enough to handle the anticipated load plus some margin. As an example, if the relays draw 400 ma, the switch is rated for 600 ma and the load is 1 A, there will still be a problem.