98 cherokee, if the vehicle is on, the defrost is on, light on switch is on, and its not just the light, cuz the rear window/mirrors start melting ice right away.

turn the vehicle off, defrost is off (i state this as i tried to google this and got some results where the defrost stayed on even with vehicle off, not my case)

where do i start to fix this? thx

 

I would start by checking behind the switch for any electrical issues.

But to me I can't really see how it is a negative thing? If it were me I'd save myself the head ache and accept the speedy ice defrost gladly.

 

Dumb question, but have you tried pushing the button again to turn them off?


You could also trade me your heated mirors, that could get rid of half your problem.

 

Sounds like your Rear Window Defogger Relay (in the Junction Block) is stuck on. The Defogger Relay also powers the Driver's Power Mirror heating element.

If you pull the cover off your Junction Block (fuse panel), in the passenger footwell, you'll see three ISO type relays (lke in the PDC), the Rear Window Defogger Relay is the bottom one in the group of three relays.

For starters, replace it. They're cheap enough. You should be able to get one from O'reilly or Advance auto parts.

If this doesn't fix it, it will require further troubleshooting.

Good luck, and get back with the results.

Cheers

 

i tried to find a raisin not to either....but i want it corrected, then i can attack my other 98 that the defrost doesnt work at all, the fixed one will help me diagnose the broken one

yep, have tried pressing the switch...no trade, i ordered heated mirrors for my other 98 that doesnt have em

10-4....im in camp for another 2 wks, so ill order a relay so its at my house when i get there and will go from there.

 

no such luck, relay tests good, swapped with horn relay as well

whats my next move? the switch itself?