Radiator fans will not work

It sounds like you are losing connection or the computer is not giving the command to close the relay. Lets use a test light to check the triggers and grounds.

Here is guide and the wiring diagrams to help you test the system:

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

Check out the diagrams (below). Please run this test and get back to us.

Cheers, Ken

My van fans will not run unless you unplug the coolant temperature sensor. Here is what I have done so far:

Replaced relay behind bumper.
Checked all other fuses and relays.
Replaced coolant temperature sensor twice.
Replaced pressure transducer.
I have checked all wires at relay. I have power, ground and signal.

The fans will run when I jump the relay harness.

The fans will run when you unplug the coolant temperature sensor.

The fans will not run when AC is on.

The fans will not run when the engine reaches the temperature in which the fans should turn on.

Help!

Hi and thanks for using 2CarPros.com. It sounds like you have already done a lot of work trying to fix this problem. What I have done is this. The first picture I have attached is the coolant temperature sensor location. There are two coolant temperature sensors on this vehicle. One is for the gauge, the other is for the computer. Check to make sure you are getting the correct one.

Next, the second picture is a flow chart for checking the fan relay. The chart is specific to this vehicle and should help you find the problem. Please keep in mind, you mentioned in your post that you have power, signal, and ground. If that is the case, it should work. Something is happening when power is sent, otherwise the fans would work.

Check out the flow chart and let me know if you find the issue.

I hope this helps.

Joe

Radiator cooling fans do not work. I replaced the fuse for the relay and relay shows it works too. I am trying to locate the temperature sensor that tells the fans to turn on. Cannot find it.

Good afternoon.

I attached a wiring diagram of the system. Check the fuse listed for power on both sides with the key on.

The engine coolant sensor is what sends a signal to the PCM. Based on that reading it will ground the control side of the relay and turn on the fans.

Roy

my radiator fans do not turn on amd my car overheats what do i need to do to correct problem

The first step is to diagnose the cause of the problem. There's three circuits to consider. The first is the coolant temperature sensor for the Engine Computer. That is not the same as the sensor for the dash gauge. The CTS tells the computer the coolant temperature, then the computer turns the fan relay on at around 210 degrees. That's the second circuit. The relay turns on the high-current to the fans. That's the third circuit and the one that usually develops the problems. The fastest way to diagnose this system is to use the Chrysler DRB3 scanner to command the fan to run. That will allow you to see the actual engine temperature to be sure the sensor circuit is working, and you can take voltage measurements in the relay circuit without having to run the engine.

Some people complained that they could actually hear the fan when it turned on. It wasn't very loud but in response the engineers came up with a continuously-variable-speed relay which is another unnecessary computer module and highly prone to failure. If you're going to guess and try random parts, the relay is the best suspect. It has four wires in the plug and usually sat halfway down along the left side of the radiator. There was a service bulletin related to it to check for broken mounting bolts. If they break the relay will seriously overheat. If it's still working it will get hot enough to burn you. It has to be bolted tightly to the body to dissipate the heat.

I have a 99 Chrysler T & C. The engine keeps overheating. I have replaced the cooling temperature sensor and the thermostat. I have checked: the fuses, all are ok; the fan motor, works; for leaks, there are none; the radiator is clean; the water pump works, heater core works. Besides that the fan does not turn on. What other suggestions do you have that could be the problem?

You need to get the cooling fan going-also could be airlock in the system if it continues get it block and pressure tested.

try the cooling fan relay, behind the inner bumper and in front of the radiator. may have to remove drivers headlamp.

Hello, I have just recently had an overheating issue with my van sitting on idle. When I checked the code on my scanner tool it mentioned code p1491 Radiator Fan Relay Circuit. I have replaced the relay and yet I keep getting the same error code and fans will still not turn on. I have checked and tested the fans(both worked but replaced them anyways). I also checked the relay for continuity, all is good. Last, I replaced the coolant temp sensor since the plastic was broken but even then the fans wont turn on. Other things i have tried was letting the car run to 221°F and disconnecting the coolant temp sensor but nothing seems to work and I still show the code P1491. What else can i do to get my fans working?

Hello, I'm Danny.

I've attached below step-by-step diagnosis/test instruction pictures below for that code.It sounds like you might be having a wiring or PCM problem. Let me know what happens after testing.Hope this helps and thanks for using 2CarPros

I have replaced the radiator in my 98 Chrysler town and country. I have also replaced the thermostat, the temp. control sensor, and the relay switch for the dual fans. The radiator fans are not coming on. any ideas on what else I can try to get this issue resolved???

The first thing is to bypass everything and apply 12 volts directly to the fan motors to see if they run. If one is tight it is likely it caused a fuse to blow.

You can also check the fan system operation by unplugging the two-wire coolant temperature sensor while the engine is running. That will turn on the Check Engine light which will go out later but it will also cause the Engine Computer to turn on the fans because it doesn't know if the engine is overheating.

The engine overheats when running in slow stop and go traffic. The two radiator fans do not come on. The air conditioner will not cool when vehicle is not moving. The fans do not come on when the air conditioner is turned on. The engine cools normally at highway speed.

I have checked the fuses under the hood. I have also tried a new relay in the position marked BLOWER. Is there any other things I can do to get this problem relolved.

Hi:
If you replaced the relay, there are two things left to check. First, are you getting power to the fan motors when it heats up? If not, you need to check the temp sensor.

Let me know what you find.

Joe

In other posts on this web site, they say that the fans should always come on when the air conditioner is on. If they do not come on with the air conditioner, does that eliminate the possibiliy of a defective coolant sensor? I have replaced the cooling fan relay, and the fans do not come on with the air conditioner. They do not come on with the high coolant temperature either. Is it possible that both fan motors are bad?

Good question. Yes the fan will come on with the AC. Before you replace anything, check to make sure if you are getting power to the fan motors. Turn the AC on and check. If you have a 2 fan system, and I think you do, only one will get power. Check it with a volt meter if you have one to make sure, if there is power, you are getting 12 volts. If there is power to the fan motor, the motor will most likely be bad. You could also unplug the motor and run 12 volts to it from the battery to see if it turns on.

Let me know what you find.

Joe

I was trying to figure out how to get power from the battery to the fans to check for function. I disconnected the left fan harness, and found that both poles on the fan motor are male fittings pointed down and nearly inaccsessable. I took the engine air filter cartridge off to get more room to work. As long as I had the air cleaner off I thought I might as well put the old radiator fan relay back, as maybe I could return it and get my money back. While I was trying to mount the old relay back on the car frame, the right radiator fan came on. The only way I could get it to stop was to unplug the old relay. When I plugged in the new relay, the fan did not come on. I replaced the wire on the left fan, and the air filter system, and started the engine. I turned on the air conditioner, and the fans do not come on. What do you think.

Wow, now I don't know where to go. Is there another relay in the box with the same part number that you can switch with the fan relay. I wonder if you have a bad relay.

I suppose I could go back to NAPA and ask if they could let me try another relay. I kind of doubt that they will, as they are $50.00 and they have a non return policy on electrical parts that have been installed. They sell two grades. One is $50.00, an the other is $70.00. Should I try the more expensive one?

I replaced the coolant temperature sensor, and the fans now work. The fans came on when I turned on the air conditioner, and raced the engine. They shut down when I shut off the air. Thanks for all the help.

I am having the same problem with my 98 t&c. So far, I replaced the radiator cap, fan relay, and temp sensor (next to thermostat housing). I also checked the 40amp fuse in the fuse box and connected the fans to the battery to make sure that they work. The fans still won't come on. What else could be wrong?
thanks,

Sorry for the late reply. I had trouble logging onto the web site that allows for this reply.

The problem you discribed is exactly as I experienced. I have no other solutions except to try another temp sensor, or relay. Maybe it could also be a continuity problem for the conductor between the temp sensor to the relay. Good Luck.