Can you use an 86-88 headlight switch on an 89-91 car? And vice versa? Mazda lists different part numbers for both, and different headlight harnesses. Most on Ebay are listed as simply 86-91, I dont want to waste money here.

 

You should have Pele rebuild yours. Then you would know it was right.

 

I need a replacement first, mine works except the parking lights stay on all the time, and i have to disconnect the battery. Cant afford to go without lights for 2-4 weeks or however long it would take to turnaround.

Anyone use a 86-88 headlight switch on an 89-91 car? Or vice versa?

 

nope, the plug is the same but the wiring diagram is way off...

 

You'll have a PM shortly.

You may also want to try a few things:

Are the dash and exterior marker lights on at the same time?
Pull the "Illumination" fuse. Do the lights go out?

On the harness where it plugs into the switch, there is a White wire with Green Stripe. It is right next to a Red wire with Black stripe.
The White/Green wire gets burned up due to a poor solder joint in the switch. If it did get hot enough, the plastic insulation could have melted off and contacted the Red/Black wire.

White/Green takes power from the fusebox (Illumination fuse) and Red/Black sends power out to the exterior lights.