Electric radiator fan not turning on

Tiny
JONNYB_2010
  • MEMBER
  • 2000 JEEP GRAND CHEROKEE LAREDO
  • 4.0L
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 180,000 MILES
I have replace the relay once already and the coolant temperature sensor. The fan motor itself is turning on with direct power and its resistance is 2.6 ohms so its only drawing about 5 amps. I just recently replaced the pcm due to another issue but the fan didn't work before that anyways. Any ideas?
Thursday, December 3rd, 2015 AT 4:14 AM

7 Replies

Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
Check the ground and check if there is a good connection at relay. The pcm controls this so also check connection at ect. See if the relay is sending power to fan it may be a broken or chafed wire as well.
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Thursday, December 3rd, 2015 AT 6:25 AM
Tiny
JONNYB_2010
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  • 5 POSTS
Ground read.5 ohms. The grey power wire 12 Volts. The green wire to the pcm read 5-6 volts when car was running and a/c turned on. Is it possible for that control wire to be shorting out and that would be why I am not see the 12v it should have
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Thursday, December 3rd, 2015 AT 6:54 AM
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
I fyou looked at the drawing I sent it shows the green wire going to fan not pcm. It shold have 12 volts. It may be a chafed wire or a bad connection at relay, make sure they are good then put dielectric grease on it for a better connection.
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Thursday, December 3rd, 2015 AT 6:58 AM
Tiny
JONNYB_2010
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  • 5 POSTS
There are two green wires on the relay. The first one is the control wire and the second goes to the fan motor
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Thursday, December 3rd, 2015 AT 7:22 AM
Tiny
JONNYB_2010
  • MEMBER
  • 5 POSTS
I just thought I should be seeing 12v from the control wire. I probably have a shorted wire somewhere I will just have to pull the battery tray and trace the wires.
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Thursday, December 3rd, 2015 AT 7:37 AM
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
The control wire is dk blue/pink and that should have 5 volts
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Thursday, December 3rd, 2015 AT 7:53 AM
Tiny
JONNYB_2010
  • MEMBER
  • 5 POSTS
Ok. That's good news. I will trace the wires and see if that is my issue. The relay could have failed again but that is usually from something being wrong with the fan.
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Thursday, December 3rd, 2015 AT 7:58 AM

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