My heater is only blowing cold air. I have changed the thermostat. Both hoses to the heater core are hot. The blend door motor isnt working. I checked heatertreater.net and I can get a new shaft that connects to the heater box to work the blend door. I thought I had found the problem but when I worked the blend door manually I still didnt get any hot air. The floor vents dont work at all and when I change the **** to the floor it blows through the defrost vents. When you try and mix dash and floor it blows through the defrost. The only settings that work are only defrost and only dash vents. I am wondering if its a vacuum leak or maybe the heater core still needs flushed even though both hoses are hot. Any help is appreciated as I am a newbie mechanic. Its starting to get a little cold around here!!!

The cruise is also not working, maybe a vacuum leak? The 4wd does engage.

 

Back flush your heater core. Then, run some water into it, with something like Limeaway, or CLR, and leave it sit for an hour or two. Flush with clean water in BOTH directions.

Vents being weird is either a vacuum problem, or, the control head is screwed up. As the control head is not a serviceable part, you have to replace the whole thing.

Your cruise not working may or may not be related. Vents, Cruise, and 4x4 all draw vacuum from the same spot. The bag o' snakes on the passenger side of the manifold. They use the plastic lines, which are notorious for getting brittle with age, and breaking easily. Check all vaccum lines, and see if there is a leak.

Cruise may also be a victim of its location. The battery likes to drip nasty things on it, and eat holes in it. Gotta remove the cruise module to fully inspect it.

Welcome to DF.

 

Backflushed the heater core like you said, refilled the cooling system and now I have some squeaking somewhere along the belt. Sounds like maybe a water pump? There is now some heat coming out of the vents but with the squeaking I didnt want to run it too long so the coolant never got up to temperature. Maybe I overfilled the cooling system? Isnt there an overflow so that cant happen?

 

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Drove it around a little bit, here is the picture of the temp gage after it warmed up and was driven around. After replacing the broken thermostat this is the highest the gage has ever read. I have heat but it isnt as hot as it could be. Definitely a difference though when I manually change the blend door. It is doing the "crazy vents" thing now where it switches from the dash vents to the defrost when I get on the accelerator, and then back to the dash when I let off. Still squeaking. Getting frustrated and cold.

 

iam pretty sure it supposed to switch from dash to defrost when on the accelerator i cant remember why tho but its supposed to do that

 

If that's a stock thermostat in there (195*) It isn't working right. (failed open.)

Wild vents is due to a failed check valve in the vacuum lines from the manifold, to the control head. Some folks have one, some folks have two.... One is right up beside the kegger, on the passenger side, oddly enough.. in the vacuum line heading back. Follow that line back, and there may, or may not... be one in the line going into the cab for the HVAC controls. Replace it. (them) Reduces the problem quite a bit.

 

FWIW, my vents weren't quite wild but did flap every now and then, and when I recently got some new vacuum lines (transfer case connections) the flapping almost completely went away. I've seen it once since then and it was on a long, steep grade.

Just for giggles I picked up a vacuum reservoir canister out of a late 70's Jeep Cherokee at the wrecking yard, and when I dive in to replace all of the under-dash vacuum lines I'm going to incorporate it into the system. After that I just dare the vents to flap!

 

Its not a stock thermostat and I havent called in to see what the temp is on it. Flushed the heater core again. I can hear the water going through the heater core when I start it and I can hear the flow increase when I accelerate. The heat also increases when I am on the accelerator and it gets lukewarm when I am stopped. I am hoping that this gets me through the winter. Do you thin I need to replace the heater core? Going to order a new blend door motor from heatertreater.net and will start to track down my vacuum issues. I checked my 4x4 and it isnt working correctly either. Thanks everyone for the input!

Just read up on burping the system. We will see if that helps the heat any!

 

There ya go. Burp it like you mean it! What you hear and think is water is actually air.

 

The blend door motor is not the problem.(don't waster your money) The vacuum leak is. Fix it and go from there.