Heater not working.
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Senior User
Joined: Dec 2005
Posts: 138
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From: White House TN.
Heater not working.
I amwondering if I have a problem, I turned my heater on this mornining and I got cold air, no heat. I took the radiator cap off while truck was still running and the fluid was not moving until the compressor kicked in and then it just dropped down a little. I am curious if it is the thermostat or the heater core, temp. is running fine and I replaced the water pump this year. I am not seeing any fluid on the floor as whena heater core leaks. By the way truck is a 93, with 177k on it. Thank you.
Fleet Mechanic
Joined: Jan 2005
Posts: 1,344
Likes: 1
A co-worker had almost the same problem. No heat, but everything else was fine. He took it to the dealer and they wound replacing a circuit board somewhere for that system. I can ask him tonight exactly what they replaced if you want.
Tuned
Joined: Jun 2003
Posts: 295
Likes: 1
From: poughkeepsie ny
Heater core might have some blockage in it, but unless you've neglected flushing the coolant for forever and a day I doubt that's the problem. It wouldnt hurt to change the thermostat. I'm not sure what you mean about the fluid 'not moving,' but make sure the level is full in the rad.
It's also possible there's a problem with the linkage that attaches the temperature selector on the panel to the heater control valve. If it came unhooked, the valve could've been left in the closed position not allowing hot water to come into the core (happened on my Honda once).
It's also possible there's a problem with the linkage that attaches the temperature selector on the panel to the heater control valve. If it came unhooked, the valve could've been left in the closed position not allowing hot water to come into the core (happened on my Honda once).
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Senior User
Joined: Dec 2005
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From: White House TN.
I have religiously flushed and cleaned the cooling system and I have a full radiator. I talked with a buddy at work who said change tstat first. I will do that this weekend and report back.Also I have a few times turned the heat on and have it and others cold so I believe it is the tstat. Thanx for all the info.
Fleet Mechanic
Joined: Jan 2005
Posts: 1,344
Likes: 1
tps93ranger,
I talked to my co-worker last night. His Ranger, like your is well maintained. He also had the same symptoms, everything looks normal but no heat. He took his to the dealer and they found a bad circuit board for the blend door motor. It sounds like the board and blend door motor are changed as an assembly. He told me the part was around $80 and over $200 for labor.
I talked to my co-worker last night. His Ranger, like your is well maintained. He also had the same symptoms, everything looks normal but no heat. He took his to the dealer and they found a bad circuit board for the blend door motor. It sounds like the board and blend door motor are changed as an assembly. He told me the part was around $80 and over $200 for labor.
Posting Guru
Joined: Mar 2005
Posts: 1,533
Likes: 1
From: Dexter, MI
What does your temperature gauge indicate - is it sitting on cold or does it show normal temp? If it is sitting on cold, replace the thermostat.
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Cargo Master
Joined: Aug 2003
Posts: 3,263
Likes: 92
From: BC Canada
Check the temp of the hoses supplying the heater core, if they are both hot the valve is working, look at blend door.
If only one is hot check the heater flow valve.
If neither is hot, check thermostat, fluid level.
HOT = >170*
If only one is hot check the heater flow valve.
If neither is hot, check thermostat, fluid level.
HOT = >170*
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Thread Starter
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Senior User
Joined: Dec 2005
Posts: 138
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From: White House TN.
Yes both of my hoses are hot and when I turn on the heat it will blow hot for a minute and then go cold. Where the hell is the blend door and does a 93, have a circuit board to control it? my temp gage reads just below normal.
Fleet Mechanic
Joined: Jan 2005
Posts: 1,344
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I would assume the blend door is somewhere under the dash. My co-worker was charged $80 for the circuit board and a little over $200 in labor to have his fixed.
Elder User
Joined: Nov 2006
Posts: 696
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From: Lynchburg, VA
Consider this thread on the blend door fix for additional info.
https://www.ford-trucks.com/forums/8...-door-fix.html
https://www.ford-trucks.com/forums/7...lend-door.html
https://www.ford-trucks.com/forums/8...-door-fix.html
https://www.ford-trucks.com/forums/7...lend-door.html
5th Wheeling
Joined: Feb 2008
Posts: 26
Likes: 1
From: Omaha, NE
Sorry for the late post, but I would go with the t-stat first. $10 vs. $80 (circuit board) - do the math. Mechnical parts usually fail before electronics do anyway.
If your gage reading is below the N in "Normal", it's not opening up all the way. With having 177k miles on the truck, it's probably time to change it out anyway - not that there's a set replacement interval. I've replaced t-stats on three of my vehicles, all different mileage - 80k, 125k & 150k, but they all had the same symptoms as yours. In fact I'm about to change one out on my son's car this weekend.
Something just occured to me (maybe something to look at too) - you said the water pump was changed...any chance some excess sealant from the gasket let loose and clogged the heater core?
If your gage reading is below the N in "Normal", it's not opening up all the way. With having 177k miles on the truck, it's probably time to change it out anyway - not that there's a set replacement interval. I've replaced t-stats on three of my vehicles, all different mileage - 80k, 125k & 150k, but they all had the same symptoms as yours. In fact I'm about to change one out on my son's car this weekend.
Something just occured to me (maybe something to look at too) - you said the water pump was changed...any chance some excess sealant from the gasket let loose and clogged the heater core?
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Senior User
Joined: Dec 2005
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From: White House TN.
Yes Burley68 I have changed the tstat in the last 3 yrs. but I am considering doing it again. I have an update, my wife and I left for a week and when we returned I once again had to use the heat but this time I turned it on defrost started warm then went cold but when I switched over to vent or floor the heat blows out hot. now what is the problem with this, is there a separate door which controls the defrost, or do I have a ghost truck(lol)?
5th Wheeling
Joined: Feb 2008
Posts: 26
Likes: 1
From: Omaha, NE
Okay, THAT sounds like it may be a cable adjustment problem. I'm pretty sure the 93's are set up with the slide control instead of the dial control like the newer models have. I have a '90 that had a similar problem in the past with the temp control. The control cable slipped and wasn't getting full cold. The function selector is set up the same as the temp control - here is the procedure for adjusting the control cable:
Sorry, can't embed the diagram, but hope this helps.
Control Cables
ADJUSTMENT
Function Selector and Temperature Selector Control Cable
To check the temperature cable adjustment, move the temperature control lever all the way to the left, then move it all the way to the right. At the extreme ends of lever travel, the door should be heard to firmly seat, indicated by a loud thumping sound, allowing either maximum or no air flow through the heater core.
To check the function cable adjustment, see that the function lever will reach the detents at the far left and right of its travel. In addition, check that the air flow is correct when the function lever is moved through each detent provided in the control assembly. If cable adjustment is needed, proceed as follows:
1. Disengage the glove compartment door by squeezing its sides together. Allow the door to hang free.
2. Working through the glove compartment opening, remove the cable jacket from the metal attaching clip on the top of the plenum by depressing the clip tab and pulling the cable out of the clip.
NOTE: The adjustable end should remain attached to the door cams.
3. To adjust the temperature control cable, set the temperature lever at COOL and hold. With the cable end attached to the temperature door cam, push gently on the cable jacket to seat the blend door. Push until resistance is felt. Reinstall the cable to the clip by pushing the cable jacket into the clip from the top until it snaps in.
4. To adjust the function control cable, set the function selector lever in the DEFROST detent and hold. With the cable end attached to the function cam, pull on the cam jacket until cam travel stops. Reinstall the cable to the clip by pushing the cable jacket into the clip from the top until it snaps in place.
5. Install the glove compartment.
6. Run the system blower on HIGH and actuate the levers, checking for proper adjustment.ADJUSTMENT
Function Selector and Temperature Selector Control Cable
To check the temperature cable adjustment, move the temperature control lever all the way to the left, then move it all the way to the right. At the extreme ends of lever travel, the door should be heard to firmly seat, indicated by a loud thumping sound, allowing either maximum or no air flow through the heater core.
To check the function cable adjustment, see that the function lever will reach the detents at the far left and right of its travel. In addition, check that the air flow is correct when the function lever is moved through each detent provided in the control assembly. If cable adjustment is needed, proceed as follows:
1. Disengage the glove compartment door by squeezing its sides together. Allow the door to hang free.
2. Working through the glove compartment opening, remove the cable jacket from the metal attaching clip on the top of the plenum by depressing the clip tab and pulling the cable out of the clip.
NOTE: The adjustable end should remain attached to the door cams.
3. To adjust the temperature control cable, set the temperature lever at COOL and hold. With the cable end attached to the temperature door cam, push gently on the cable jacket to seat the blend door. Push until resistance is felt. Reinstall the cable to the clip by pushing the cable jacket into the clip from the top until it snaps in.
4. To adjust the function control cable, set the function selector lever in the DEFROST detent and hold. With the cable end attached to the function cam, pull on the cam jacket until cam travel stops. Reinstall the cable to the clip by pushing the cable jacket into the clip from the top until it snaps in place.
5. Install the glove compartment.
Sorry, can't embed the diagram, but hope this helps.
Thread Starter
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Senior User
Joined: Dec 2005
Posts: 138
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From: White House TN.
OK update,I changed the tstat and no change. I have checked the defrost door, its working. I checked today and now one hose is getting hot and not the other. I had a few people tell me it might b a control valve in my heater hose and I have looked and have nothing in my heater hoses. any chance it might b somwhere else, dont know just asking. I am becoming frustratedwith this sucka. Everything seems to b working ok.