Someone explain this cooling fan wiring diagram

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Apr 27, 2010
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2013 Nissan Versa with A/C and has one cooling fan with two connectors. Fan doesn't work but I can hear the relays clicking when activated by a scan tool. Why does the wiring diagram show 3 fans? And I see the low and high speed relays but what is that third relay for?


radiator fan wiring diagram.jpg
 
I think they are showing one schematic for both a/c (one and two connector configs) and non a/c vehicles. It looks like non a/c vehicles have only one motor which is referenced E3. Having A/C with two connectors, you would have motor E5. Ignore motors E3 and E31. Looks like that 10 amp fuse is for the fan circuit.
 
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A car built with A/C and one fan is the "CP" configuration, which means the single fan motor is the one in the center of the diagram, E31. The other two motors shown apply to "CN" or "CQ" cars, which you don't have.

When the fan is supposed to be on, use a voltmeter to probe the motor connector between its live wire and its ground wire. If voltage is reaching the motor but it doesn't turn, it's a bad motor.

The third relay closes the ground circuit on the second high-speed brush. With the high relay on but that relay open you'd get an intermediate speed. But the fan should at least turn in any case.
 
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The CQ fan is wired to exactly the same places as the CP would be, only the pin numbers are different.
 
How does the fan roll by hand? Is it still the OEM fan assembly? Typical failure on these is the motor bushings loose their lube and go bad. Really common on Nissans.
 
I put 12V to the high and then the low speed output wires at the fuse box that goes to the fan and both cause the fan to work. Fan motor and connectors are fine.
 
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The electric cooling (no AC) fan on our '85 Mazda 626 had fused power (12 V) running directly to the fan, with the interruptible ground path running through the relay. The relay was NC (normally closed), and power was applied to it, opening the gund circuit, when the coolant-temperature sensor detected that the fan was not required.

Thus, the cooling fan circuit was the fail-safe type - that is, if the relay lost power, it would close, providing a ground path and turning the fan on.

I'm finding the schematic confusing on my phone, but I would start with the basics - check for 12 V at the fan motor, and if power is present, I would run a ground wire from the motor's ground terminal directly to ground. If the fan operates, then the grounding relay is bad or is not getting the correct signal to operate, or there's some other fault in the ground circuit.
 
It's the dang fuse. One of those 50A squares with the see through top cover that don't have any test points like regular fuses. I had already pulled it out to test for continuity but it showed good. I should have thought something wasn't right as it came out and slid back in pretty easy. Looks like it wasn't making good enough contact. Jumped the terminals in the fuse box and fan is working like it should.
 
Correction. It looks like there are different lengths of these fuses. Someone put a too short one in. Found a long one and it fits like it should.
 
The only fuse is a main fuse then. That should have shut down several other things. If the diagram is right, failure at the "BATTERY" point means the ignition relay and ECM would not get power, which would probably prevent the car from starting.

If stuff is loose or melted in the fuse box you really need to replace the whole box. When a bad connection overheats the spring temper of the contacts is lost, and putting a new fuse in will still be a bad connection and burn up again.
 
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Maybe I wasn't clear about the fuse. The left one was in the car and wasn't long enough to reach the pins in the fuse box. I put in the right one and it now works.

IMG_8119.JPG
 
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