own a 1995 jeep cheroke,the thermostat housing was changed few months ago and since then my jeep doesnt heat up. I have replaced 4 thermostats in last 2 weeks, the gauge fluctuates alot and the needle is about half way between the 40 and 100. Before all this it sat just shy of the 100. Now that the cold weather has arrived -35 (c) and it will not warm up, we also had the heater core flushed. What can we do.