Replaced lightswitch on 96 Jeep Cherokee. When I turn the headlights on the parking lights go out

easy with head lights, the work even KEY in pocket.
the battery terminal lugs never cleaned ever.
a loose main fuse. in PDC.
you losing 12vdc main power.
trouble shoot the headlight path or parking lights (1 click)
parking lamps are brutal simple. and for sure on any old 96

loose or faulty wire

To keep the switch from arcing and wearing out, they use a relay. The dimmer switch turns the relay on and off, so does not use as much current. The relay is a small plastic box plugged into the fuse box, along with several other relays.

I would look at replacing the headlight switch(junkyard will save you money)!

Hope this sheds some light on it!

Review this info: ZJ-Secc-8L-Lamps (page Lamps 8L-5 and next)

Good luck, and rated me!!!

Honestly, I think you have a bad part. It's not uncommon, especially with electrical items. Speak with your parts person and they should warrenty the part. Another switch should cure things.
Good luck.

Recap of my problem:
no parking lights, have headlights, light switch seems to have sweet spot that turns on both head lights and parking lights.

Solution is:
Blown fuse on 15, it works the radio, parking lights, dome lights.

The headlights are on a relay and maybe its getting weak. I would have it checked and replaced because it could go out and stay out.
God Bless Greg
Oh yeah most of the time it is built into the head light switch.

Check the relay for you headlights. It seems like you are only getting juice when in hi-beams are on and not lo-beams. Or maybe the lo-beam portion of you headlights are burned out. There are 2 filiments inside the light, one for hi and one for low.