Overheating

Tiny
BIKERBILL34
  • MEMBER
  • 2003 NISSAN ALTIMA
  • 4 CYL
  • 2WD
  • AUTOMATIC
2003 Nissan Altima, Radiator fans don't come on and engine overheats. What sensor drives the fans?
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Monday, December 20th, 2010 AT 10:55 PM

4 Replies

Tiny
SATURNTECH9
  • EXPERT
It's the engine coolant temp sensor.
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Monday, December 20th, 2010 AT 11:26 PM
Tiny
WRENCHTECH
  • EXPERT
That's controlled by something called an "Intelligent Power distribution Module" which is controlled by the ECM after referencing the coolant temp sensor. There are (2) 40 amp fuses to check also. Here are the wiring diagrams and coolant sensor location and the location to the cooling fan relays.

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

Check out the diagrams (Below). Please run some tests and get back to us.

Cheers
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Tuesday, December 21st, 2010 AT 12:18 AM
Tiny
BIKERBILL34
  • MEMBER
I've checked the fuses, and all 3 fan relays check good. The coolant temp sensor was replaced, so its new. I'm kinda stuck, don't know anything about these Japanese cars. The only fan that comes on with the a/c is the blower. I bypassed the fan relays and can make both fans come on. However the relays check good. I've got good voltage to the coil side of all three relays, however there is no ground. So I swapped out the ECM with a used one my buddy had and everything works again :) ya. Thanks for your help and diagrams with guides you guys are the best.
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Tuesday, December 21st, 2010 AT 3:29 PM
Tiny
WRENCHTECH
  • EXPERT
Glad you could get it fixed, that kind of problem can be tough. Please use 2CarPros anytime we are here to help

Cheers
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Thursday, December 23rd, 2010 AT 9:32 PM

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