2002 ram 1500 4.7 heater not working

[sbelasco76]

When the truck heats up, I can turn the defroster on and for a brief time it blows warm, not hot but warm. This quickly goes away and becomes cool not cold. If i turn the fan off and wait, i can do it again, over and over. I changed the thermostat and back flushed the core how ever i did notice that there seemed to be some resistance when back flushing. not sure how free flowing it should be. i removed most of the dash and as far as i can tell all the actuators seem to be working and all blend doors are moving freely, again as far as i can tell. I have burped the system and pretty sure no air is trapped. Im really hoping its not the core....Does anyone have any similar experiences that could help me?















Sam

 

[jws123]

Make sure coolant is not low/no air in sytem can be a bit annoying to bleed. Next make sure your thermostat/waterpump is good if all that checks out flush heatercore with hose both ways. If that fails time for a heater core its a 2002 its honestly not to bad of a job as its a 1 piece dash takes 1 day.

 

[drakon543]

just as long as its not like my 01 durango. all electric and it has to be calibrated so it actually knows what position all the doors r in. doesn't work right at all if it loses its calibration