1998, 4 wheel drive ram 150 heavy duty class. I only get cool or now that it's winter weather cold air coming out of heater.I've seen no water on interior carpet and checked inlet and outlet pipes on heater core,one being warm and the other slightly less warmer. Is there a fuse that could be bad or thermostat problem before i order a new heater core?

 

Wouldn't be a fuse.

 

Does your engine get up to temp? Is the radiator full?

 

 

Could be a blend door, try putting the blower on full and changing the temperature from full hot to full cold. Does the sound of the air moving change? If it doesn't the door that directs the air from the blower to the evaporator or the heater core might not be working. Do you get more heat if you rev it up? If so there may be a restriction in the heater core. Heater core flush might fix it for a while depending on how plugged up it is.

 

Yep,my temp. guage warms to same temp as far as i can tell and about a mo. or less i checked radiator level and needed small amount less than 12 oz and that's just a guess but it wasn't much. I've made two trips from N.J. to N.C. this summer and i keep a close watch on my gauges . thanx for your reply.I am a real novice at this but it could very well be that blend door. I first just went in the dash through the glove box to see if i could find the heater core and when i did i found what felt like a mechanism of some kind that i could move and i opened or closed it , im not sure because i couldn't see it but i did notice that when i moved it that it had a connection with the hot to cold adjustment and i thought i opened it to the hot . I will recheck it and try that coil flush you suggested. The truck has other issues to but it is all i have right now for transportation and i did see a video on youtube that looked pretty helpful on removing the dash and dropping the steering column if i have to replace the heater core. thank you again.

 

thanx for your reply,I will check that out.

 

Thanx for your reply.