Ok Here is the problem. My dad's truck is a 1998 5.9 1500. The truck has 126,000 miles. The truck has no heat. We have cleaned and flushed the radiator and heater core. The truck gets up to operating tempature but still has no heat coming out of vents. We have done everything we know to ensure the heater core is full. I noticed the AC compressor is coming on and going off a lot when the switch is in any position. I checked the switches and the vent doors in the dash are working properly as well as the tempature switch. Is the AC compressor supposed to be cycling this much even when just the heat is on? How can I get my old man some heat?

Thanks
Joe

1998 Dodge 1500 4x4 5.9 engine.
2011 Ram 1500 4x4 5.7 Hemi.

 

im having the same problem, i believe it is air bubbles in the cooling system. Search how to burp you cooling system and see if that works

 

The compressor should only cycle when you select defrost (and max AC...) if its cycling when you select the floor/panels there's a problem. If its cycling more than 4 times a minute your AC system is over or undercharged and that needs to be fixed.

+1 on getting air out of the cooling system

If that's all set and you have no heat, feel the heater hoses (inlet and outlet) both should be real warm and about the same temp, if not the heater core is clogged or there might be a restriction elsewhere.

 

Heater core is clogged.

 

^ +1 lol