2003 radiator fan relay

[brianw217]

hey guys i really need help........ my 2003 grand caravan radiator fans wont work. right now i have them hot wired to a switch but i dont like the idea of it. background... where to begin. i have replaced the coolant temp sensor twice and still have the same problem. i checked it with the multimeter and the voltage does change as the temp increases. i have also replaced the relay and the 40amp fuse in the block. i do notice that when the engine is running i get about 6.2 volts going to the radiator fans if they are disconnected but as soon as i plug the pigtails in the voltage drops. there is 12v going into the relay and if i jump the connection the fans run. this may be confusing so msg me if u need me to clarify anything. i really would like a wiring diagram of the fan system with voltages but can not find any.. please any help is greatly appreciated

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[master tech]

Replace the fan relay. Its in the front bumper fascia on the passager side. You'll need to remove the fascia.

[brianw217]

Already Replaced it but the fans still don't work. When I disconnect the coolant temp sensor the fans don't run and the same goes if I turn on the a/c. Could there be an I line fuse somewhere? If I had a shop manual or a wiri g diagram with the voltages it might help

[kev2]

Is the CEL on?

I am having trouble posting the diagram for you .....

To get you going ..
terminals at relay
1- org/red wire 12v from 40amp fuse
2-dkblu/dkgrn 12v to fans
3-dkblu/vio signal from PCM
4- blk/dkgrn ground -relay and fans

I agree the relay is suspect- new does NOT mean good.
you might try using a DVOM selecting A/C and probing terminal 3 for voltage...checking for command from PCM

LET us know

[brianw217]

1- org/red wire 12v from 40amp fuse
2-dkblu/dkgrn 12v to fans
3-dkblu/vio signal from PCM
4- blk/dkgrn ground -relay and fans

k ill have to take the fascia off this week. its been a cpl weeks since i had it off but heres what i remember ill post the other voltages when i get it off.

1- org/red wire 12v from 40amp fuse---12v
2-dkblu/dkgrn 12v to fans---6.2v (but when i plug in the fans the voltage is 0v
3-dkblu/vio signal from PCM-----
4- blk/dkgrn ground -relay and fans----0v

[brianw217]

disregard my last post here are the voltages i get

1- org/red wire 12v from 40amp fuse---13.26v
2-dkblu/dkgrn 12v to fans--6.02v (0v when i plug the pigtails into the fans)
3-dkblu/vio signal from PCM----0v
4- blk/dkgrn ground -relay and fans---13.26v (if this is the wire all the way on the opposite side of the org/red wire

[brianw217]

im guna assume that there is a short somewhere between the computer and the ground or even a bad ground

[kev2]

If you probe the fan circuit (#2) be sure to unplug the fan -
this will seperate wiring from the motors.

what about the question is the cel on?


ARe you back probing? or probing just harness?
ck terminal #4 -eng off- for ground.

[brianw217]

The CEL is on i cleared the codes but still get 2 codes saying that the coolant temp sensor voltage is to high and too low. i have replaced the coolant temp sensor twice so i dont know why it would be saying that.

the fan circuit shows 6.02 volts when the fans are unplugged. when i plug the fans back in the voltage is 0v. i was probing the wires right off the harness while it was plugged in.

this may sound stupid but how do i check for ground with my multi meter?

[kev2]

The codes are 1st step now.
post the code #s pxxxx- sometimes confusion as to description and many eyes will catch that

with the harness connected to module and probing the circuit is backprobing ....

doing this- with engine running what is activity on PCM circuit with A/C on and then off?

Disconnect BOTH ends of circuit...confirm meterr* ...one probe to ggouund other probe to wire ... any reading other than infinity is
suspect..

*touch probes together checking tool watching for reading..