Got my dad's 99 Dakota R/T. The heater has not been worth beans since he got it. While my Durango heats up within 6 miles and gets hot inside, the Dakota can drive 40 miles and only get luke warm, if even that. He had a new thermostat put in once and it improved for a short while and then back to luke warm. Does the resister have anything to do with heat and A/C or is there some other solution?

 

Are you low on coolant? Does the engine heat up? If your good on those its likely just a plugged up heater core. Pull the two hoses going to it in the firewall and use a hose to push water through it both ways. If that doesn't help then you're likely going to need a new heater core. Unfortunately that means pulling the dash out of the truck and is a huge and time consuming job.

 

Ouch! Could it be something else? It hasn't gotten much heat since brand new.

 

Not sure if these trucks have a bypass valve to turn off flow to the core when its not needed but if they do that could be a culprit. Pretty sure it wouldn't have anything like that since that body style is still using vacuum controls. Might be a bad core from the factory I suppose but I've never heard of that before. I would try flushing the core since that's easy and just takes a few minutes.

 

No heater valves. The temp is controlled by a blend door, which may be the issue.

 

Thanks for everyone's imput. Does anyone know what the resister under the dash do? Does it have anything to do with A/C or heat?

 

The resistor block is for fan speed. Had nothing to do with air temp.

 

Thanks.