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2003 Nissan Altima Repair Question


Topics covered: Sensor, Coolant, Engine.
Mileage: No information provided.

Asked on December 20, 2010

2003 Nissan Altima Overheating

2003 Nissan Altima, Radiator fans don't come on and engine overheats. What sensor drives the fans?
Avatar Asked by bikerbill34

Answer

Replied on December 20, 2010

It's the engine coolant temp sensor.

Tiny Answered by saturntech9 (expert)
23,193 answers provided
Replied on December 21, 2010

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 Answered by Wrenchtech (expert)
14,757 answers provided
Replied on December 21, 2010

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 Response from bikerbill34
1 question asked

Replied on December 21, 2010

Will any fans come on with the A/C?

Tiny Answered by Wrenchtech (expert)
14,757 answers provided
Replied on December 23, 2010

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 Response from bikerbill34
1 question asked
Replied on December 23, 2010

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

Tiny Answered by Wrenchtech (expert)
14,757 answers provided