My cooling fan dies not come on at or around 90 degree Celsius. I've checked the fuse and the fan motor and they're both good. I unplugged the coolant temp sensor when engine was cold and the fan would come on right when engine was started. I checked continuity on the sensor and got 2.4 kohm. After the engine running for a bit I plugged the sensor back in and the fan shut off and I got the temperature reading. When I unplugged the sensor again the fan stayed off. Could I have fooled the computer to thinking it's cold to keep the fan off? Can a temp sensor give temperature readings but not turn the fan on? Thank you. Also with engine cold I mean sitting outside in minus 20 Celsius all day.
Cooling fan doesn't come on
- Thread starter Jordmich
- Start date
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renegade 04
Full Access Member
The engine cooling fan will not even kick on till the engine temperature is around 214 degrees fahrenheit.
Royy
Full Access Member
Actually, 214 Fahrenheit is 101 degrees Celsius.
The thermostat doesn't even open to allow coolant into the engine until the engine temperature reaches 90.5C (195F). So at that point there is no need yet for the fan to be on.
The thermostat doesn't even open to allow coolant into the engine until the engine temperature reaches 90.5C (195F). So at that point there is no need yet for the fan to be on.
Generally the electric fans will come in an A/C position or any defrost setting as well.
I recently tested my fans set in heat mode only, and hooked into OBD2 port with Scangauge.
Fans came on while parked at 219F and shut off as it cooled down, at 214F.
I recently tested my fans set in heat mode only, and hooked into OBD2 port with Scangauge.
Fans came on while parked at 219F and shut off as it cooled down, at 214F.
I will double check to get better reading. When I was testing it few days ago it got to 114 Celsius which is 237 ferenheit. I'm asking if my sensor could read correct temp but not send the signal for the fan to come on? It makes no sense to me how it could but you never know I'm no mechanic.
Here is some good info link: http://www.jeepkj.com/forum/f196/help-fan-relay-57994/
Do you have a clutch fan as well as the Electric fan?
How are you obtaining temp readings? Plugged into OBD2 or?
Does the fan come on when A/C or defrost positions selected?
Is the analog dash temp gauge above half or?
Is the dash engine light on at all, indicating a stored code? Fan relay code?
I wonder if the subzero temps in Alberta may skew the readings by a few degrees as well.
Do you have a clutch fan as well as the Electric fan?
How are you obtaining temp readings? Plugged into OBD2 or?
Does the fan come on when A/C or defrost positions selected?
Is the analog dash temp gauge above half or?
Is the dash engine light on at all, indicating a stored code? Fan relay code?
I wonder if the subzero temps in Alberta may skew the readings by a few degrees as well.
I'm getting the temp from a reader.
The fan does not come on when ac is turned on. If I unplug the sensor the fan comes on and a get a high coolant sensor circuit fault as well as a low one. I.dont.know if the computer is sensing the sensor is faulted when unplugged and leaving fan on all the time just in case or what. I switched the relay with another one that's the same and it made no change. Other than the fuse, relay, temp sensor, fan motor what else could it be? Am I missing something? Thanks again for the reply
The fan does not come on when ac is turned on. If I unplug the sensor the fan comes on and a get a high coolant sensor circuit fault as well as a low one. I.dont.know if the computer is sensing the sensor is faulted when unplugged and leaving fan on all the time just in case or what. I switched the relay with another one that's the same and it made no change. Other than the fuse, relay, temp sensor, fan motor what else could it be? Am I missing something? Thanks again for the reply
Is the A/C charged and in working condition?
If Yes...You could have 2 problems.
Start by replacing the coolant temperature sensor with a new MOPAR one.
Then onto Fan relay if required, and Mopar again there.
If Yes...You could have 2 problems.
Start by replacing the coolant temperature sensor with a new MOPAR one.
Then onto Fan relay if required, and Mopar again there.
What year are we talking about here, or did I miss it? The efan systems changed a bit over the years.
02 and 03 (maybe some 04) had a one speed fan and a large relay under the battery tray on the inner fender. After that they switched to a two speed with two relays in the power dist center under the hood. When my 02 relay went I got a CEL and an appropriate code. I believe if either of the relays fail for the 2 speed system, you will also get a code. I would test the fan itself first as I believe if it craps the bed it will not give a code. So try to put 12V directly to the fan itself and see if it works before doing anything else.
Yes fan is good I put it off battery directly and works good. If I unplug temp sensor in morning when engines cold the fan will run once engine is started just won't shut off. It's an 06 liberty. Basically the fan will stay on all time with sensor unplugged. If I plug the sensor in after coolants warm then unplug again then my fan wont turn on. I found a list of resistance for temp sensors ( generic ones not mine specifically) and it said the fan should come on when the sensor warms and reaches around 600 ohms. After I drove it the lowest I saw was 4k ohm hot and 44k ohm cold. If only reaching around 4k ohm than wouldn't be low enough to trigger fan to come on. Again though that's not specs for my specific sensor but just general ones I found online.
uss2defiant
Full Access Member
sounds like you already troubledshoot the cause.
change the coolant temp sensor then.
change the coolant temp sensor then.
I feel that way too I just wasn't 100 percent about it. I can't think how the sensor would send a temp reading to my dash gauge but not tell the fan to turn on when needed. I just wasn't sure. Also not sure how the sensor for coolant temp would keep the fan from running when I put the ac on?
uss2defiant
Full Access Member
The e-rad fan only comes on at certain conditions.
OPERATION
The electric radiator cooling fan is controlled by the Powertrain Control Module (PCM) through the radiator cooling fan relay. The PCM regulates fan operation based on input from the engine coolant temperature sensor, battery temperature sensor,air
conditioning select switch and vehicle speed. The fan is not energized during engine cranking regardless of the electrical input from the temperature sensors and ,air conditioning switch. However, if engine operation conditions warrant fan engagement, the fan will run once engine starts.
Vehicles Equipped with AC:
In addition to using coolant temperature and battery temperature sensor to control cooling fan operation, the cooling fan will also be engaged when the ,air conditioning system is activated. The relay is also energized when, air conditioning is selected and coolant temperature is above 95° C ( 203° F), or , air conditioning is selected and battery temperature sensor is above 41° C (106°F). It will then de-energize when , air conditioning is selected and coolant temperature is below 92° C (198° F), or , air conditioning is selected and battery temperature is below 38° C (100° F).
OPERATION
The electric radiator cooling fan is controlled by the Powertrain Control Module (PCM) through the radiator cooling fan relay. The PCM regulates fan operation based on input from the engine coolant temperature sensor, battery temperature sensor,air
conditioning select switch and vehicle speed. The fan is not energized during engine cranking regardless of the electrical input from the temperature sensors and ,air conditioning switch. However, if engine operation conditions warrant fan engagement, the fan will run once engine starts.
Vehicles Equipped with AC:
In addition to using coolant temperature and battery temperature sensor to control cooling fan operation, the cooling fan will also be engaged when the ,air conditioning system is activated. The relay is also energized when, air conditioning is selected and coolant temperature is above 95° C ( 203° F), or , air conditioning is selected and battery temperature sensor is above 41° C (106°F). It will then de-energize when , air conditioning is selected and coolant temperature is below 92° C (198° F), or , air conditioning is selected and battery temperature is below 38° C (100° F).
Ok yes that makes sense. So if air conditioning is turned on when engine is cold the fan will turn on also? Or even with the ac on the coolant still has to get warm before the fan will kick in? So this sounds as though the only possibility is the sensor. Let's say I keep the fan unplugged like it is right now since the fan is running can I assume the relay is fine and the other thing that could be faulty us the cool temp sensor? Thanks again
uss2defiant
Full Access Member
with the AC on it depends on the coolant temp or the battery temp.
so if the coolant temp is not greater than 95C or if the battery temperature is not greater than 41C the AC will not engage. it is a conditional OR.
your symptoms sound exactly like the thread LibertyTC posted which was a bad coolant temp sensor.
so if the coolant temp is not greater than 95C or if the battery temperature is not greater than 41C the AC will not engage. it is a conditional OR.
your symptoms sound exactly like the thread LibertyTC posted which was a bad coolant temp sensor.
uss2defiant
Full Access Member
You probably mean the coolant temp sensor unplug.
yeah. the relays are probably fine but I don't know which relay is kicking on at this point. since you have a 2005 with a 2 speed fan.
The earlier models' fan speed is PWM controlled.
