Need help with heater
#1
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Year: 1989
Model: Cherokee
Need help with heater
So I am kind of new to jeeps but have been around cars all my life. So here is my problem. I have a 89 XJ and the entire cooling system is new except the heater core. I am getting warm air when it sits and idles. When I get it on the highway or around town it will go to ice cold. Now the really crazy part is the jeep will never over heat. It barley reaches 210. I took the fan and fan clutch off and run just the electric fan off a switch but never have to turn it on. Also when I am driving if I have the vent on heat which is the floor it will switch to defrost. Any help or suggestions I can try I would greatly appreciate it.
#2
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Welcome to the forum. Your 89 will have a Renix specialist here soon.
In the meantime, what I understand from (at least non-renix) " going to defrost setting" (for instance if you accelerate) , is that this has to do with vacuum loss. As a default, it will go to the defrost setting.
In the meantime, what I understand from (at least non-renix) " going to defrost setting" (for instance if you accelerate) , is that this has to do with vacuum loss. As a default, it will go to the defrost setting.
#3
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Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Welcome to the forum. Your 89 will have a Renix specialist here soon.
In the meantime, what I understand from (at least non-renix) " going to defrost setting" (for instance if you accelerate) , is that this has to do with vacuum loss. As a default, it will go to the defrost setting.
In the meantime, what I understand from (at least non-renix) " going to defrost setting" (for instance if you accelerate) , is that this has to do with vacuum loss. As a default, it will go to the defrost setting.
Here is a vacuum diagram of the vacuum system below.
As for the heating issue, begin by replacing the thermostat with a 52028186 from the dealer and flushing your heater core.
#4
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Year: 1999
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Here's a functional diagram of the AC/Heater system.
As pointed out, a vacuum leak may be causing your problem, including loss of vacuum to the water valve in the engine bay.
.
As pointed out, a vacuum leak may be causing your problem, including loss of vacuum to the water valve in the engine bay.
.
#5
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Thanks for the info. Ill have to check those out because I don't think I saw the vacuum canister under there. I have flushed the system twice already and change the thermostat twice. Ill go get one from the dealer and try that one.
Last edited by JimmyE; 02-17-2016 at 11:16 AM.
#6
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Thanks for the diagrams. But as far as the water valve it is no longer there. So I know that's not one of the problems.
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#9
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So I defiantly do not have that in my bumper. But will that not being there cause the heat issue or is it more just for vent control?
#12
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Year: 1999
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Check security and operation of the Blend Door cable on the bottom of the HVAC Unit.
You should be able to move the bottom slider on the AC/Heater control back and forth and see the Blend Door bell crank arm move from side to side.
See pic.
.
You should be able to move the bottom slider on the AC/Heater control back and forth and see the Blend Door bell crank arm move from side to side.
See pic.
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