hmm odd... Ive only had AC problems not heater problems. So when you turn the heat all the way up to the highest temp and turn the little snowflake lookin symbol off it still blows cold? ive never heard of that

 

Did you Check to make sure your coolant level is full?

 

Yes its at the line, Ill re check though

 

Okay I was low on coolent, but unfortunately it didn't change anything.. still blows cold tested for 10 minutes

 

Sounds like maybe it's a bad thermostat?

 

I had this problem on my 2000. My mechanic figured it was probably a plugged up heater line so he took an adapter he made which combines a garden hose and a low pressure air line and hooked it up the heater lines. Between the low pressure water and the turbulence provided by the low pressure air he was able to blow out the heater core and heater lines and restore the heat. Maybe that's all it is for you.

 

bumping for more help

 

I'd suspect a bad blend door actuator.

 

check for an air lock, fire up your truck and open up your rad cap. i had this on my blazer few years back. no heat at all or comes and goes? running the truck with the cap open will bleed any air out in the system, might work.

 

I'd suspect a bad blend door actuator.

This is what I was thinking too. Just replaced one of these to fix the Wife's Tahoe.

 

The way to rule that out would be to see if both heater hoses are hot, no?
If the heater hoses aren't hot at all then it's probably thermostat related.
If only one is hot, or there's a significant temperature difference between the two, then it's probably a blocked heater core.
If they're both hot but there's no heat, then it's probably the blend door or similar.

 

Which 2 hoses should be hot? When I felt them before neither were hot at all but i wanna be sure I'm touching the right one

 

I wasn't able to take off the plastic tip above the grill to get to the rad cap but in will asap, does anyone have a diagram of the hvac hoses? Or a helms manual so I know where the thermostat and all the hoses are located

 

The heater hoses are generally two hoses that go to the same place into the firewall. Usually on the passenger side of the vehicle and up higher. They're probably 1" hoses.

 

Okay well. I'm not sure how long it's suppose to take for them to heat up but I ran the heater for 5 minutes and went and grabbed them and they had a cold feel to them

 

Should've had something in five minutes, at least a noticeable warming. My guess is that it's the thermostat. Otherwise the truck warms up properly and runs well? Your temperature gauge remains in the normal operating zone?

 

Yes everything else with the truck runs smoothly and sound, other than a Upstream 02 sense needing replaced and an oil change soon ive had no problems and temp guage remains before the halfway mark as it always has.

 

do this:
disconnect your two heater hoses at the engine side. hook a garden hose up to one of them and see if water comes out the other. If not then your heater core is probably blocked.

 

While you've got the hoses off. Take the garden hose and run water into either side of the heater core. Do this a couple of times on each side. This will rinse out the core. It that works be propared to do it next winter too.

 

Blend door actuator.

It's under the dash, smack in the middle, next to the floor. Three 7mm screws to hold it in. Take the actuator off, then move the door by hand. If the blowing air changes from cold to warm, you need a new actuator. OReilly's stocks it - about $45.

 

okay going to try that in just a bit!!

 

Blend door actuator works fine :/ now. I'm. Stumped

 

I plugged everything back in but now My hvac system won't turn on unless it's on 5

 

Bump. For help

 

I'm about to hook up a water hose and flush out the hoses.. Does anyone know which hose is the in and which is the out?