97 cherokee heater issue

I am having a problem with my heating system

the fuse inside the one for the heater the 15 amp blows when you start the vehicle i unhooked the relay the switch and the blower and still at the turn of the key it pops

i am lost any input would help

That would be a "short to ground". Take the heater control switch unit out to see if it got fried.

Got it!

The Jeep had an aftermarket alarm system in it and it was causing a short.

I removed the harness and that took care of the fuse blowing.

Thanks

Got it!

The Jeep had an aftermarket alarm system in it and it was causing a short.

I removed the harness and that took care of the fuse blowing.

Thanks

Yep, that is how you fix electrical harness problems. Take every thing apart and start testing and looking. Plus some luck, which you must have had.