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Discussion Starter · #1 ·
Hey guys,

So my spec v has a koyo radiator and 2 Spal fans that were installed from the previous owner. When I start the car neither fan is on (obviously). When I turn the AC on, the compressor turns on and then the passenger side fan turns on. When the car gets up to temp, the same fan will stay on regardless of AC. The driver's side one doesn't seem to turn on ever. The AC is nice and cold when it works but if I'm idling for awhile, I hear the compressor shut off and then it gets warm until I start driving again. After reading through many threads and forums, it could be a number of things, a bad relay, not enough refrigerant, or bad wiring in the fans. I wanted to see what any of you thought for my exact problem as I couldn't find this exact issue anywhere with a specific answer. Any help is appreciated!
 

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yes, if it the refrigerant on the high side is too hot a sensor should flip stopping the compressor, this sensor can be either digital or analog base on how it stops the compressor, this action is called reaching "high limit". and kicks back on when pressures and temperature is back to normal. at least that's what happens in residential split and heat pump units that has temp and pressure sensors.

1 fan is not enough to cool down the condensing coil. I am running off 1 fan and it's a struggle when i am in traffic.
 

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Or could be a bad fan. Try and make it work or check for power to it.. Compressor cuts off because there is no airflow across the condenser, increasing the pressure and the pressure switch keeps it off until the high side drops.

Cant remember exactly how the wiring is but I think both are powered by high ac and coolant temp because its converted from a single fan to a dual??
 

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Discussion Starter · #9 ·
You think it could still be a bad fan even though both turn on when plugged into the same wire? Or were you just replying to my initial post? Could another test be swapping the relays around?
 

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My bad think I skipped your last post by accident. Yup swap relays. I was trying to find a wire diagram to see but gave up lol.
 

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How many wires go to each fan ?
On my Xtrail QR25DE I have 4 wires to the main dual-speed fan and 2 wires to the secondary single-speed fan.
As a test you can disconnect the temp sensor plug and use a 150 Ohm resistor across the sensor harness plug terminals. This simulates a high engine temp and both fans should run with the dual-speed fan at high speed.
 

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Discussion Starter · #13 ·
I believe it's 2 wires for both fans. When I go to swap the relays, I'll take pics too. It's too hot outside right now so I'm waiting til it cools down haha. Where exactly is the temp sensor plug?
 

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Discussion Starter · #15 ·
Okay I swapped the relays and the same fan turned on when I turned the AC on. I'm assuming if a relay was bad and I swapped them, the other fan would turn on with the AC. Or is that wrong? Here are pics of the wiring. 2 wires from both fans connect into a connector with two wires that looks spliced into 4 wires.
Auto part Wire Electrical wiring Tire Electrical supply

Auto part Fictional character

Auto part Wire Plumbing Engine Fuel line

Auto part Pipe Tire Automotive tire Carbon


Also, Revhead, is this the connector you're talking about?
Auto part Fuel line Engine Automotive fuel system Vehicle
 

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OK so it looks like the Spal fans which have been installed to replace the 2-speed OEM fans are only single speed and the wires have been spliced together so they operate from both high and low speeds.
If you get yourself a diagram of the OEM fan wiring for your Sentra you should be able to determine from the wire colors which is 12V and which is ground to make sure everything is connected correctly. My wire harness colors for the Xtrail could be different from your Sentra wire harness colors.

It would be worth it to undo the splices to check the OEM wires individually for the correct voltage and make sure there are no loose connections when you connect them back together.
 

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Discussion Starter · #17 ·
This is the wiring diagram I found. I'm not too savvy with wiring so it's a little confusing for me. I understand the color codes, just not exactly whats going where.
Diagram Technical drawing Text Plan Circuit component
 

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Discussion Starter · #19 ·
By redo, do you mean just undo the splice and splice again where the connector is or the actual wiring to the harness is bad and needs new wire?
 

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The original wiring has 3 fuses, 3 relays and 2 dual-speed fans.
ECM output 37 turns on Relay-1 for low speed of fan-1 from fuse I and of fan-2 from fuse H through terminal 1 on each fan to ground terminal 4 on each fan.
ECM output 27 turns on both Relays 2 & 3 for high speed of both fans. Relay 2 is for fan-1 high speed from fuse I and relay 3 is for fan-2 high speed from fuse H. High speed wiring is through terminal 2 on each fan with ground running through the same relay from terminal 3 on each fan.

Low speed 12V for fan 1 is Yellow with ground Black
High speed 12V for fan 1 is Green/Yellow with ground White/Blue

Low speed 12V for fan 2 is Green/Red with ground Black
High speed 12V for fan 2 is Blue/Black with ground Yellow/Black

If you have a bad fuse 20 then no fans will work since this supplies 12V to all relays.
If you have a bad fuse I you will have no low or high speed for fan 1.
If you have a bad fuse H you will have no low or high speed for fan 2.

If you have a bad relay 1 you will have no low speed for both fans.
If you have a bad relay 2 you will have no high speed for fan 1.
If you have a bad relay 3 you will have no high speed for fan 2.

I think I have the low and high speeds te correct way around but just check your service manual to make sure relay 1 controls low speed for the fans, otherwise reverse the above descriptions.
 
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