Where is the termostat in the 2008 kia optima 2.7 V6 and how do you replace it?? The heat does not work in the car .. but yet it doesnt overheat. I was told the first thing to do is to change the thermostat.

I've got an issue with the 4X4 on my Jimmy, I recently purchased this vehicle knowing it had 4X4 issues. When I first got it the lights on the push button switch on the dash would sometimes not come on and the "service 4X4" light would come on. If I cycled the key several times sometimes the "service 4X4" light would go off and the lights on the push buttons on the dash would light back up and I could use the 4X4. Finally it quite working. I checked the control module behind the passenger kick panel and the large orange plug was all wet and corroded (sp), I cleaned the plug conections and still nothing worked. I replaced the module. Now when I start the vehicle all the lights on the dash push 4X4 switch light up momentarily and then go out and the "service 4X4" light comes back on, is there a way to check the transfer case motor? Any other test suggestions would be great!! Thanks, Ben