Coolant fans will not turn on

Tiny
DAVES68NOVA
  • MEMBER
  • 2005 DODGE CARAVAN
  • 3.8L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 104,698 MILES
I jumped the power wire at the plug to the other side and both fans come on high speed if there is only one. I turn on the A/C and fans won't turn on. When I unplug the coolant temperature sensor then the fans cone on and stay on until I plug the temperature sensor then the fans go off.
Friday, December 20th, 2019 AT 11:33 PM

5 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
Good morning,

If you remove the plug to the coolant sensor and the fans come on, the wiring to the fans is working as it should.

I would start by replacing the coolant sensor itself and see if it works.

Does the engine reach normal operating temperature on the gauge? A bad thermostat will also cause this issue.

As far as the fans not coming on with the AC, the fans will only come on when the high side reaches 150 pounds of pressure. With the weather being colder, it may not come on.

Roy
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Saturday, December 21st, 2019 AT 6:11 AM
Tiny
DAVES68NOVA
  • MEMBER
  • 3 POSTS
Thank you. I will Try replacing the thermostat and temperature sensor and your right with the temperature being so cold it's hard for the van to reach really hot, but the heat is excellent. Some reason coolant seems to be coming out somewhere because there's steam. I put Leak Detection Dye in the coolant that way I can find where it is leaking or coming from. Thanks for your help, Dave
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Sunday, December 22nd, 2019 AT 4:45 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
You are welcome.

Always glad to help.

Roy
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Sunday, December 22nd, 2019 AT 4:47 PM
Tiny
DAVES68NOVA
  • MEMBER
  • 3 POSTS
I found a few weeks ago that there was a small leak in radiator causing the coolant to not reach the temperature sensor could not turn on fans so, I flushed all old coolant, new radiator, new coolant and new pressure cap. Now works perfect. Thanks guys. You guys do a awesome job with what you do. Dave
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Sunday, March 1st, 2020 AT 10:54 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
You are welcome.

Always glad to help.

Please feel free to leave a review for us.

https://www.google.com/search?q=2carpros&gs_ivs=1#lrd=0x80dcd47364be5d0d:0xba091aa4209f4497,1,,,&tts=0

https://www.sitejabber.com/reviews/2carpros.com

Roy
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Monday, March 2nd, 2020 AT 4:32 AM

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