Ok my Fiance has an 03 ranger xlt that is giving me problems and I just cant pin point it. She told me one day that her heater wasnt working so I started by checking the blend door actuator. discovered not working so I got a new one and still no luck. So I have made sure the core is getting hot and it is, if i move the blend door by hand all works great! I have checked the temp switch and I find no power going to it but there is power to the BDA. I grounded out the switch and the BDA did move. The fuses all check fine indoor and underhood. So here i sit scratching my head
OOOHH How I love to point out wrong answers::: As I have stated there is NO POWER to the BDA (Blend door actuator) "The part that moves the Blend Door" the Blend Door is JUST FINE IE: NOT BROKEN!! It is an electrical problem!
The heat in my 96 4 cyl. only works normal when the truck is moving. When idling in the morning for longer than 10 minutes with the heat contol on hot the air from the vents is cool until i start driving down the road when the vent air starts getting warm like normal, at stoplights for longer than a minute the temp starts getting cool until i start moving down the road. Any ideas ? I already replaced the "heat valve box" in the heater core hose lines.
Sounds like a coolant flow problem . How is the temp gauge reading ?
Check the radiator hoses , esp. the inside to make sure they are not collapsing .
Check the coolant level in the rad itself , not just the reservoir.
Replace the thermostat.