no heat

Heater core not leaking. All knob selections like defrost, feet, face work. blower works fine. warm air is all I get. At one time it would drive you out of the cab if turned up hot. I will flush core and make sure the control valve is manually open. ?????? Do not know what else would cause very little heat!!

 

Assuming the temp gauge tells you the truth, engine gets hot as normal right?

Did this happen all of a sudden?
Change the antifreeze for a 50/50 mix...nothing more..nothing less.

Remember to bleed air out of the system (fill rad with nose pointing up, on stands or better on a steep hill).
Might just be an air pocket in the heater core.
Flush and proper fill will confirm this.

Failing this, the heater core has junk blocking circulation..
To prove, touch nigoing and out going hoses if possible.
Both should be about the same temp as the engine is heating up.

 

I understand the situation with bleeding system . confused about why controls do not activate the valve. open or close??
no movement of cable so I disconnected and tried opening and closing heat control valve. pretty simple but no change . I will flush core and try making sure all air is gone from system???

 

your truck is 15 years old and may have multiple issues.
Was the coolant changed evey 5 years or so?

If the fan is working...and the core is getting hot (both hoses are hot).
My next question would be, is the fan blowing any air?
Are you getting better volume at ,...say the windshield,...but little at the floor (trap issue).