No Heat OR A/C
Thread Starter
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Tuned
Joined: Feb 2007
Posts: 461
Likes: 1
No Heat OR A/C
My truck vents are just blowing out ambient air.
It doesn't matter if I turn the temp **** to the coldest setting or the hottest setting, the temp does not change. The air coming through the vents is whatever the temp is outside the truck.
I do not believe it's a problem with the vacuum pump, as I can choose which vents activate; defrost, panel, foot. I have vacuum at the white line under the glove box and I can see the blend door opening and closing, so nothing is stuck there.
No climate control system mods and both heater hose are hot to the touch.
After first experiencing the problem yesterday, there was a time when everything was working fine. The A/C was blowing ice cold and when I tried the heat it got hot quickly. That didn't last long though.
I'm off to use the search function, but any input is appreciated.
It doesn't matter if I turn the temp **** to the coldest setting or the hottest setting, the temp does not change. The air coming through the vents is whatever the temp is outside the truck.
I do not believe it's a problem with the vacuum pump, as I can choose which vents activate; defrost, panel, foot. I have vacuum at the white line under the glove box and I can see the blend door opening and closing, so nothing is stuck there.
No climate control system mods and both heater hose are hot to the touch.
After first experiencing the problem yesterday, there was a time when everything was working fine. The A/C was blowing ice cold and when I tried the heat it got hot quickly. That didn't last long though.
I'm off to use the search function, but any input is appreciated.
Logistics Pro
Joined: Jun 2005
Posts: 4,243
Likes: 16
From: AZ
From your description, it sure sounds as though the heater core or input line has become plugged. Bring the truck up to operating temperature and check the lines going to the heater core (one will be bringing the hot water to the core and the other will be bringing the water back to the engine). With the heater on full hot and the fan on, the return line should be significantly cooler than the input line. If they are about the same temperature work back towards the engine on the heater core input line and find where the temperature gets much hotter...that is the place where the blockage is occurring. PM me if you want the repair manual diagnosis...
Thread Starter
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Tuned
Joined: Feb 2007
Posts: 461
Likes: 1
coolant is good.
I just went outside to run the heat and feel the hoses. This time the climate control worked as it should. As the truck came up to temp the cabin got warmer. In feeling the hoses there was a slight temperature difference. Not night and day but certainly a few degrees by feel. IIRC, the hose on the right side of the engine was a little warmer than the hose going to the center of the block.
When I switched to A/C the cabin got cold and the temperature between the hoses became drastic with the one hose barely warm but the other very hot.
That all sounds as it should, doesn't it?
I just went outside to run the heat and feel the hoses. This time the climate control worked as it should. As the truck came up to temp the cabin got warmer. In feeling the hoses there was a slight temperature difference. Not night and day but certainly a few degrees by feel. IIRC, the hose on the right side of the engine was a little warmer than the hose going to the center of the block.
When I switched to A/C the cabin got cold and the temperature between the hoses became drastic with the one hose barely warm but the other very hot.
That all sounds as it should, doesn't it?
Post Fiend
Joined: Sep 2006
Posts: 5,584
Likes: 0
From: Millbrook Alabama
Originally Posted by firemediceric
coolant is good.
I just went outside to run the heat and feel the hoses.
When I switched to A/C the cabin got cold and the temperature between the hoses became drastic with the one hose barely warm but the other very hot.
That all sounds as it should, doesn't it?
I just went outside to run the heat and feel the hoses.
When I switched to A/C the cabin got cold and the temperature between the hoses became drastic with the one hose barely warm but the other very hot.
That all sounds as it should, doesn't it?
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Junior User
Joined: Oct 2005
Posts: 95
Likes: 0
From: Vancouver, BC
Mine did this one time, I had no heat, and then all of a sudden 20 minutes later it started blowing out hot air, now it works fine.
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Thread Starter
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Tuned
Joined: Feb 2007
Posts: 461
Likes: 1
Originally Posted by bdrummonds
The heater core is a coiled loop, the temperature of the return should only be slighlty lower than the input temperature. Are you sure there is not a heater core cut off valve plumbed into those lines? It would take a mighty strong blast of cold air to cool of a coil of 196* coolant. me thinks you've got something stopped up.
From other reading that I have been doing, I am beging to think it's a problem with the white servo behind the glove box.
Logistics Pro
Joined: Jun 2005
Posts: 4,243
Likes: 16
From: AZ
Originally Posted by firemediceric
If it were an obstruction, I wouldn't think that the problem would be as intermittant as it has been yesterday and today.
From other reading that I have been doing, I am beging to think it's a problem with the white servo behind the glove box.
From other reading that I have been doing, I am beging to think it's a problem with the white servo behind the glove box.
ON Edit: I just went to check out the diagnosis in the manual...here is the heater/ac diagram. It would appear to me that if part #4 (temperature blend door) was stuck open, the air would travel over the air conditoner core (#5), but not over the heater core (#11)...thus no heat. Now, if for some reason the door came unstuck, heat would flow. Check fuse #24 (10 amp)...if it is blown, replace...if it isn't blown I'm now putting my money on the electronic blend door actuator to be the fault.
Last edited by nlemerise; Nov 14, 2007 at 10:30 AM.
Thread Starter
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Tuned
Joined: Feb 2007
Posts: 461
Likes: 1
Originally Posted by nlemerise
I'm now putting my money on the electronic blend door actuator to be the fault.
Logistics Pro
Joined: Jun 2005
Posts: 4,243
Likes: 16
From: AZ
Originally Posted by firemediceric
I think what you're referring to as the "electronic blend door actuator" is the same thing as the "white servo behind the glove box" that my other reading is pointing to.