No heat

I've got a large bill I'm paying off at my local shop but there is more to fix on my 2002 so I need to see what i can learn on my own. Its getting colder than a witches tit up here and my truck doesn't make heat. The blower works but it only blows cold air, I checked for coolant and the reservoir and radiator itself has coolant in it. What else should I be looking for?

 

When you turn the dial or slide the lever from cold to hot can you see the movement of the water valve / heater control valve? Located about center of the vehicle on the firewall.

 

It does not move

 

That valve on the firewall opens and closes according to what you have selected inside for hvac. We talking the 95 taco or the 02?

 

The 02, and the valve does not operate when I turn the dial.

 

https://www.youtube.com/watch?v=AT9WAhJ6apE

 

When it's warmed up, CAREFULLY touch the hoses going into the heater core, the hoses going into the firewall after that valve we want to see that they're hot or not

 

I will check it out tomorrow in the daylight, I'm checking the hoses at the fire wall?
Oh after watching that video it makes more sense, didn't realize the heater core is in the cab

 

Search the term heat and posted by me. I first replaced the unit in the dash but that wasn't it. Mine turned out to be the air mix servo motor. Bought one from a part out and replaced it. That worked. It's located under the dash by the passenger's left foot.

You can try to unhook the cable from the valve to make sure the valve works and can be moved by hand. If it doesn't move by hand then might need to replace the valve.

 

The valve lets hot water to the heater core. Blower pushes air over the heater core and makes hot air.

 

I can't move it by hand

 

And that's with the cable unhooked from the valve that you cannot get that valve to turn, right?

 

I did not unhook the cable, but I couldn't physically move it at all by hand, it was pretty rusty

 

The cable is stiff and is supposed to be what moves that valve open and closed. On the other end of cable is a little electric servo motor. We're trying to see which component isn't working right. That valve should be movable with the cable disconnected. With the cable disconnected you can turn the knob inside and verify that cable moves. That little motor that moves the cable is a somewhat common failure point on the 01-04s, if they have issues with HVAC

 

^^This.

You really have to slide that cable off the arm on the valve and then try to move that arm back and forth.

If it still doesn't move then you need a valve. About $85 ish for OEM but aftermarket options are out there as well.

While the cable is disconnected have a helper move the dial from cold to hot (I think key must be in the on position as it's electric) and see if the cable moves.

If the cable doesn't move then it could be the servo motor, (aftermarket options are available) which is replaceable with a phillips head screwdriver and a mirror laying on the floor in the passenger footwell so you can see what you're doing up there. Or, there have been cases of the cable being seized in the sheathing. Might be able to shoot some lube in there and free it up or replace the cable.

 

I wonder too if someone removed the thermostat.

 

I removed the cable and the valve does open and close by hand, I turned the valve but the truck still doesn't make heat.

 

It seems to me that both hoses going through the firewall are pretty hot.

 

So with the truck on do you see the cable moving when turning the dial from cold to hot?

If not you can pull the servo and test it as shown in the thread I referenced above.

 

The cable does not move. But with the valve open without the cable on it shouldn't the truck blow heat?