I turn my heater on and it never get's warm. I also can't change where it comes out, deforst, feet, face, etc, it's always stuck on defrost. I can increase the power from 1 to 4 and that works fine, but I can't change it or get it out. Any ideas?

 

sounds like a vacuum problem. the controls (except speed) is controlled by vacuum. so you might have a vacuum leak also theres a little valve towards the heater core above the oil filter heater control valve or something that has a vacuum connection and if that comes off it wont let coolant through to go to the heater core.

EDIT: this is on a 95. 98 might be different.

 

Your heat coming out of the defrost only most likely is caused by a missing vacuum ball. It's in your front bumper on the passenger side. Either it's missing or the line isn't attached or broken.

Regarding having no heat your heater core is probably clogged up or shot. Get yourself a radiator flush kit with cleaner. About $10-15 and it cleans out the block, rad, hoses and heater core.

 

Do I need to flush it? Or can I just pour it in and leave it?

 

Any chance its my thermostat?

 

Thermostat wouldn't cause no heat. It would cause overheating though. And with regards to flushing, letting the cleaner sit wont do the job. You probably have gunk in your heater core and you have to have pressure, ie; the garden hose, to push those contaminants out. It's very cheap to do and will clean everything out. If that doesn't do the trick Id say your next bet is a new heater core

 

The thermostat WOULD cause you to not have heat, but only if your engine is not getting up to operating temprature. Is it at the correct temp or is it running cool? If its running cool then your thermostat is stuck open and that will cause the heat not to heat up since the engine is constantly cooling. Im having the same issue right now and Im on my 4th t-stat. I will be buying one direct from a dealership here shortly as Ive been told that they are the best ones to get for our Jeeps.