Charlie57

Basically I have no heat. I have changed the thermostat and not sure what to try next. both heater hoses feel warm which makes me think the water is circulating, the fan is blowing.
What should I try next?
Charlie

qdeezie

Check your vacuum lines and move the heater temperature control back and forth and listen for the blend door opening and closing. If you hear nothing, check for vacuum leaks first. If no vacuum leaks, possibly a blend door issue.

Charlie57

I just took off the control panel and looked, the wire that controls the hot and cold is fine and you can see it moving and hear the door moving also. I also moved the lower controller and could hear the vacuum sound.
I also removed one heater hose and forced water into it from the my water faucet and the water came out to the radiator.
Now I am really stumped!

Chris_1

iTrader: (1)

Look under the hood passenger side on top of the heater box by the firewall. Look for a vacuum line going to an actuator. Have someone operate the controls on the dash while you see if you can tell if anything is happening there.
You can also pull the vacuum line off and see if you are getting vacuum/no vacuum as the controls are moved.
If everything is ok there, maybe it's air in the system. You can get a Prestone flush tee to put in the heater hose which is a good way to bleed off air, but the truck will do it itself eventually.
That works best on a bit of an uphill incline so your rad cap is the high point - then get it good and hot, let it cool right down. Get it good and hot again, let it cool right down. Eventually all the air gets pushed out to the overflow bottle which you keep topped up to the fill line.

Mountain Time

Also, if you have a slow leaking rad and your fluid drops to a certain point, your heater might start blowing cold, happened to me anyway. fixing my rad problem (just replaced it) fixed my heater problem.