OVERHEATING

2003 Nissan Altima

Tiny

bikerbill34

December, 20, 2010 AT 10:55 PM

2003 Nissan Altima, Radiator fans don't come on and engine overheats. What sensor drives the fans?

FOUND 12909 RELATED QUESTIONS

6 Answers

Tiny

saturntech9

December, 20, 2010 AT 11:26 PM

It's the engine coolant temp sensor.

Tiny

Wrenchtech

December, 21, 2010 AT 12:18 AM

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.

Tiny

bikerbill34

December, 21, 2010 AT 3:29 PM

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.

Tiny

Wrenchtech

December, 21, 2010 AT 4:02 PM

Will any fans come on with the A/C?

Tiny

bikerbill34

December, 23, 2010 AT 8:46 PM

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. Im guess ing this is how the ECM controls fan speed, by switching the ground? I'm so lost, LOL

Tiny

Wrenchtech

December, 23, 2010 AT 9:32 PM

Yes, the ground is the control trigger. You have no way to test that module though.

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