HEATER NOT WORKING

Tiny
CVALCIK
  • MEMBER
  • 1996 DODGE RAM
My truck only has luke warm heat. I flushed the cooling system, new thermostat, OEM 195 degree, flushed heater core many times, water free flows very strong through heater core. I have a spot on my temperature knob that sticks a little. I opened the dash, took out the temperature control panel and the cable and gears all seem to work well. Hoses to and from heater core at the firewall are hot. If it is the "door" the temp. Control knob controls, how and where do I get to it? Is there a vacuum control on this vehicle also? Where? Do I need a heater core? Any help would be great, thanks!
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Saturday, December 16th, 2006 AT 3:27 PM

32 Replies

Tiny
DONVAN
  • MEMBER
I ended up changing the heater core and it fixed the problem. It took about 6 hours and was a pain but the heat is HOT now. Good luck!
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Monday, January 15th, 2007 AT 11:08 PM
Tiny
JPAM
  • MEMBER
Thanks cvalcik for posting back here for the update. WE thank you.(2carpros. Com) sorry no one posted back in Dec.

Thnks jess s
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Tuesday, January 16th, 2007 AT 2:06 PM
Tiny
TIMMM
  • MEMBER
I have the same problem with my 96 4x4 ram 1500. I've tried everything listed in the posts and more. It all started after the recall dodge had on plennums. They have had the intake off mine a few times while under warranty and ever since then I can get very little heat. I'm just kind of living with it now. Sucks when it is minus 40' C. I hate to just change the heater core and then find out thats not the problem. I've already had the dash out once. I even cut the heater hoses and inserted pressure sensors to see what the pressure was like. Everything seems good and yet very little heat.

Now my 4 wheel won't engage. I'm thinking acuator. Has anyone a suggestion here. Does it work on vacume and acuator.
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Thursday, January 18th, 2007 AT 3:10 PM
Tiny
CNOVOT
  • MEMBER
Do you over heat? If so I would check under your oil cap. If you have a white film on ityou need to replace your Head gasket. I had the same problem on an older truck but I also replaced what you did and I was getting pretty mad.
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Friday, January 19th, 2007 AT 7:56 AM
Tiny
TIMMM
  • MEMBER
Hey donvan my truck has never overheated. I have pretty much given up on the heat problem and learned to live with it.

Do you know how the 4x4 engages. Is it engaged by an acuator or vacume or both. Mine just quit for no apparrent reason.
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Friday, January 19th, 2007 AT 8:48 AM
Tiny
SELLARS
  • MEMBER
Timm the 4 wheel drive is ran by vacuum and my 98 has the same prob havn't got it fixed but thats what mine is!

Cvalcik how much did ur heater core cost?
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Tuesday, November 6th, 2007 AT 8:34 PM
Tiny
TIMMM
  • MEMBER
It turned out that the acuator was not my problem at all. It turned out the vacume line was off on the intake manifold. It was hard to see right away. Make sure your vacuum lines are hooked up or they are free of holes.

Timmm
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Wednesday, November 7th, 2007 AT 8:29 AM
Tiny
JJANDRICK
  • MEMBER
I own a 1998 Ram 1500 and I am having all of the symtoms. Poor heat, 4x4 shift fork will not engage. I have troubleshot the vacume to the transfer case valve. I get no vacume out of the 2 lines going to the shift fork. I am trying to find out I fmaybe the lines are clogged aor if I am goint to have to pull the transfer case to go in to detail on this. I have also thought of just bypassing the valve and just put in a manuall valve to engage the axle. Any suggestions? Also when I really romp on the accelerator my heter controll redirects the the air flow?
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Sunday, December 2nd, 2007 AT 3:14 PM
Tiny
PA1719@ATT.NET
  • MEMBER
Also am having the same problem as jjandrick. I noticed either heat or a/c on when you accelerate it diverts the air to the defrost and then when you let off it sounds as if there is a door in the middle of dash that closes. I see there is a vaccuum actuated diaphragm on the side of the heater box under the dash. Is this getting weak or is the another problem.
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Sunday, December 9th, 2012 AT 8:51 AM
Tiny
DRVR9225
  • MEMBER
  • 1996 DODGE RAM
Heater problem
1996 Dodge Ram V8 Two Wheel Drive Automatic

I have replaced the thermostat and have topped off the coolant level but I do not have coolant flow through the heater hoses and both of them are getting hot what ccould be the cause?
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Saturday, January 19th, 2019 AT 11:54 AM (Merged)
Tiny
JACOBANDNICKOLAS
  • EXPERT
If both hoses are getting hot, then you have flow through the heater core. Make sure the blender door is working allowing the heat from the core to enter the truck.

Joe
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Saturday, January 19th, 2019 AT 11:54 AM (Merged)
Tiny
SCHUELLER74
  • MEMBER
  • 1996 DODGE RAM
  • 6 CYL
  • 4WD
  • MANUAL
  • 334,000 MILES
I recently bought this truck and the heater is blowing luke warn air on low fan speed when I turn the blower up it blows cold air. I grabed the heater hose on both sides and they felt like they were both about the same temp, both hot. At first I thought it was the theromstat because the engine wasnt getting hotter than 160 degrees, but now im getting 190 degrees with cardboarrd in the grille. Any sugestions thanks, NIck
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Saturday, January 19th, 2019 AT 11:54 AM (Merged)
Tiny
JACK42
  • MEMBER
If both hoses are hot, the heater core should be flowing. This may be a blend door (Temp door) actuator problem under the dash. Turn from hot to cold and see if thetone of the airflow changes. IF not it may need a new actuator
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Saturday, January 19th, 2019 AT 11:54 AM (Merged)
Tiny
77MARINE85
  • MEMBER
  • 1996 DODGE RAM
  • 5.9L
  • 4WD
  • AUTOMATIC
  • 240,000 MILES
I have a Cummins. Change heater core no heat. Installed flush t and flushed no heat. Not over heating. Thermostat is working as well as the water pump. AC works. By pass door works. Read that the AC/heater fan switch could be the culprit, because it actuates the AC compressor and a motor that switch air from heat to the evaporator. I do not know how to test the switch. Any thoughts would be appreciated. Driving around with a propane heater is getting old.
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Saturday, January 19th, 2019 AT 11:54 AM (Merged)
Tiny
HMAC300
  • EXPERT
I am assuming you mean no heat in truck. First check cable for blend door to see if it is broken or not operating the blend door so you can get heat.
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Saturday, January 19th, 2019 AT 11:54 AM (Merged)
Tiny
MORT64
  • MEMBER
  • 1996 DODGE RAM
  • 5.9L
  • V8
  • 2WD
  • AUTOMATIC
  • 180,000 MILES
New pump new thermostat, flushed x2, New rad cap. Heat gauge gets and stays at norm running temp until I turn on heater fan then drops to approx 170 degrees and doesn't recover until I turn it off. Temp is Luke warm at that point. If it's a blend door accurate motor where is it? Is it difficult to fix?
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Saturday, January 19th, 2019 AT 11:54 AM (Merged)
Tiny
HMAC300
  • EXPERT
This has a cable for a blend door operation, check to make sure it's not broken and that it moves door rod. However the door rod may be broken from the door and not opening. Also there are a couple of vacuum motors by gas pedal make sure there are no vacuum leaks.
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Saturday, January 19th, 2019 AT 11:54 AM (Merged)
Tiny
MORT64
  • MEMBER
Thanks this is very helpful, I do know there aren't any vac leaks. This maybe a cheap fix other than my time thanks again !
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Saturday, January 19th, 2019 AT 11:54 AM (Merged)
Tiny
MORT64
  • MEMBER
But doesn't answer the question of why it drops to approx. 170 degrees when fan is turned on.
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Saturday, January 19th, 2019 AT 11:54 AM (Merged)
Tiny
HMAC300
  • EXPERT
Because the blend door may be letting to much cold air in heater. Also check radiator for cold spots after warmed up. It should be the same all across if not the rad is not good.
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Saturday, January 19th, 2019 AT 11:54 AM (Merged)

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