I have a 2001 ram 1500 with the 5.2l V8. My heat has been barly working only on the 2 lower settings. Once I put it on the two higher it comes out cold. I was thinking thermostat but im not sure. Any ideas?

 

Did you try backflushing the heater core

 

When the truck is up to temp feel the heater hoses. They should both be hot. If not the heater core is most likely clogged as stated above.

 

My heater core just been flushed and my stock tstat put back in. It gets warm but not hot on full blast.

These trucks must just have bad heat or something.

 

No. A properly functioning heating system will literally roast the occupants in the cabin.

 

^ True that.

Edit:

My blend door is screwed up, so I only get heat/air out of the defrost vents, but it still roasts the cab.

Might need to flush or burp the coolant system. I had a blockage somewhere along the line to/through/out of the heater core and I had no heat because of it.

Burping can be done by having one side of the front higher than the other, like up on a wheel ramp, I usually have the passenger side up, engine running with radiator cap off and check for burps, refill with coolant as needed until the burps stop and the fluid levels out, check heat.

 

A heater core with pinhole leaks can cause low heat issues.

 

A buddy of mine has a 2001 2500 and his heat is amazing. He had a serious leak in the heater core and he put some stop leak in it and it works great now, he also replaced
The tstat. Thanks every one!