on cold mornings, after i get my truck started, the heater doesnt blow hot air, but i can hear something when i switch the vent control....

 

May have a vacuum leak somewhere in your 4WD system ! Is it not switching from defrost to heat...?? Are you only getting defrost ??? Or is it that your system is just not getting hot ????

 

Are you getting any air out of any of the vents (floor, dash, defrost)? Does it sound like the blower motor runs? Turn your key on, but don't start the truck. Switch the blower to high and turn it to any of the vent settings. You should hear the thing startup.

 

this is an intermittant problem.... heat will work fine when the truc is warm, when i go to start it on a cold morning nothing happens!!

 

The heater extracts heat from the engine coolant, if the engine is cold or the temp gauge is laying on "C" you wont get any heat until it warms up and these big 7.3's can take a while to warm up

am I reading this correctly? the heater is blowing but it is blowing cold air when the engine is cold?

 

sorry ill try to re-word

intermittant problem with blower not turning on.... it will be on the setting to be full blast, nothing blowing, then after 20 minutes of driving it will start blowing out of nowhere

 

Yep, mine does same thing. Not nice when you need to keep the windshield defrosted. I'm pretty sure it's the blower. It's not something I want to do in the cold, so I think I'm going to wait. Plus I don't know how big a job it is. Maybe you can let us know when you're done.

 

lol, got ya. Ya never know though.

I had the blower motor go out on my truck a few years ago, sometimes it would work sometimes it wouldn't.

sometimes electrical motors will get a bad spot in the armature that will prevent it from starting. Kind of like the lill electric racecars we played with as kids. You would get a bad spot on the track and they wouldn't work so you would push it ahead a few inches and it would take off, as long as you han momentum when you hit the bad spot the car would keep going.

Same thing could be happening here. Bad spot in the armature of the blower motor...when you shut off the truck the blower stops there and wont start until you drive down the road and rattle it around so so it moves off that bad spot.

there are 2 things to do to check that.....if you start the truck and the blower isn't working pop the hood and tap on the blower motor. It's located on the passenger side firewall pretty much just below where the radio antenna mounts. If it doesn't start up you need to pull the electrical connection off the motor and see if there is voltage there. A digital volt meter would be best for this but a test light should work with the fan switch set on high. If there is no voltage there the problem will be in the switch or wiring.

Give that a check and let us know what you find.

if it is the blower it is easy to change, three screws I think then swap the fan cage and you have to swap the electrical connector from the old motor to the new motor. maybe 30 minutes total and about $40 from napa for a new blower motor.

 

thank you!
will try when i get back into town next month...... i miss my truck!!!