Assuming your thermostat is working correctly and the wiring to the temp sender is ok low coolant could be a possibility.

You have not checked the coolant level?

I'd avoid putting cardboard in front of the radiator, that will fix nothing.

 

I did check it in the spring when I was fixing this. It's confusing as to what i'm reading, that low coolant would cause it to not heat up seams like it should be the opposite way.

 

The low coolant may not fully submerge the sensor or allow air bubbles to be in the presence of the sensor, resulting in an inaccurate reading.

Make sure the coolant is full.

 

I'll check that. Just to cover all my bases how exactly would I go about filling it up? Seams self explanitory but if you don't mind.

 

http://www.jeep4x4center.com/knowle...um=cpc&utm_campaign=Morris4x4+LC+Affiliate+Program&utm_content=Branding+125x125

This should link you to a service manual and hopefully right to the cooling system information.

 

Tuche.