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i have 2012 jeep grand cherokee overland 5.7l i recently juat changes the thermostat, radiator, and water pump but i notice that the temp still climb above 212°F but if i turn on my ac the Fan outside turn on to cool down truck but if i turn ac off the temp climbs. Plus cold air only blow thru my system no heat when i had the temp on 84° CAN SOMEONE PLEASE TELL WHAT DOES THIS SOUND LIKE.
 

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I dont see a post that relates my truck running hot without ac running and when ac is on the temperature seem to be ok
 

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I don't have my service manual handy to look at the wiring, but to me it sounds like the temp sensor to turn on the fan relay is not working. When you turn on the AC it should always turn on the fans, bypassing the temp sensor.
 

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Yes as soon as i turn on ac compressor clutch clicks and you hear the fan start to go so if i have my ac blasting the fan when keep up with the speed of the blower motor
 

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....Plus cold air only blow thru my system no heat when i had the temp on 84° CAN SOMEONE PLEASE TELL WHAT DOES THIS SOUND LIKE.
....that sounds like the system is low on coolant..... ....if the coolant level gets to low, 1st it will stop circulating through the heater core, then it will start running hotter than normal.....

Only with the engine cold, open the pressure cap on the radiator (it can scald you if you open it hot) and make sure the coolant comes within an inch of the lip that the pressure caps seals on, if not, add coolant and add the right coolant, bad things happens when you add the wrong coolant and they are not compatible.....

A 2012 Jeep should be HOAT coolant, Zerex G-05 is the exact same thing as the Ford/Chrysler/Mercedes HOAT Coolant its dyed the Ford Amber instead of the Chrysler orange/pink because more fords than Chrysler's use it.....

The overflow jug level is not the way to judge the cooling systems level, if everything is working 100% correct and the system had been properly filled and purged originally, yes it will reflect the actual level of the system. If the system has the slightest problem or wasn't filled and purged properly, then the overflow jug can show a very different level than the rest of the system.

Like you said, when you turn on the AC, it turns on the fan that actually cools the engine as well as the AC.....
If your coolant level is low, the fan coming on earlier might help..... ....normally in winter, when I have the AC off, despite being very cold out, when I sit at idle at a light the water temp goes up as high as 220°F before the fan turns on full and cools it back down to 203°F... ....but will moving it always stays at 203 or below. In summer, when I have the AC on, and the fan is going high for the AC, the temp doesn't go up while sitting at a light.... ....this is normal.... ....if you're running 118°F at a steady cruise down the road over 25mph, then yea, you're running hot...
 

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....that sounds like the system is low on coolant..... ....if the coolant level gets to low, 1st it will stop circulating through the heater core, then it will start running hotter than normal.....

Only with the engine cold, open the pressure cap on the radiator (it can scald you if you open it hot) and make sure the coolant comes within an inch of the lip that the pressure caps seals on, if not, add coolant and add the right coolant, bad things happens when you add the wrong coolant and they are not compatible.....

A 2012 Jeep should be HOAT coolant, Zerex G-05 is the exact same thing as the Ford/Chrysler/Mercedes HOAT Coolant its dyed the Ford Amber instead of the Chrysler orange/pink because more fords than Chrysler's use it.....

The overflow jug level is not the way to judge the cooling systems level, if everything is working 100% correct and the system had been properly filled and purged originally, yes it will reflect the actual level of the system. If the system has the slightest problem or wasn't filled and purged properly, then the overflow jug can show a very different level than the rest of the system.

Like you said, when you turn on the AC, it turns on the fan that actually cools the engine as well as the AC.....
If your coolant level is low, the fan coming on earlier might help..... ....normally in winter, when I have the AC off, despite being very cold out, when I sit at idle at a light the water temp goes up as high as 220°F before the fan turns on full and cools it back down to 203°F... ....but will moving it always stays at 203 or below. In summer, when I have the AC on, and the fan is going high for the AC, the temp doesn't go up while sitting at a light.... ....this is normal.... ....if you're running 118°F at a steady cruise down the road over 25mph, then yea, you're running hot...
I agree with that ^
Your engine's basic coolant system needs some attention.
The aux fan when turned on with the AC is masking the problem.
 

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Today i also found out whybi didnt have no heat my hoses for the heater core was not connect as well as one of the plugs was plugged into out and in of the heater core connector piece so not i have heat and it look like it dont want to over heat since thw other guy did say the normal temp is about 203° but today i was able to drive and the temp truely stayed below 190 when i was driving and once i stop it was 163°
 

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Today i also found out whybi didnt have no heat my hoses for the heater core was not connect as well as one of the plugs was plugged into out and in of the heater core connector piece so not i have heat and it look like it dont want to over heat since thw other guy did say the normal temp is about 203° but today i was able to drive and the temp truely stayed below 190 when i was driving and once i stop it was 163°
Its hard to read what you wrote, could you try again?....

If the heater core was hooked up backwards, I can't imagine why it wouldn't still work. As well, if its not hooked up well, that would mean its leaking.... ...did you check the level and top off the cooling system?

You still have a problem, now your engine is running too cold. 190° is only slightly low, but 163°F is way to low. You need a new thermostat.... ....once the engine is warmed up, my 5.7L doesn't go below 195°F, perhaps 194°F at the lowest in the coldest ambient and lowest low....
 
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