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Old 05-21-2013, 06:45 AM   #5
Tally HB
The Old Guy
Join Date: Feb 2013
Location: North Florida
Age: 57
Posts: 721
Vehicle: 1989 D21 Base 2WD 2.4L
Thanks: 23
Thanked 100 Times in 80 Posts

To do this install you need the fans of course, you need to have eliminated the fan clutch and fan blade (which is done in another of my write-ups) so you have room for the fan to clear the water pump pulley.

You will be wiring this fan system up so that they work on and off automatically by coolant temperature.

To do this you need a fan control switch that grounds at 195 degrees. This switch runs to the relay ground leg that, when grounded by the switch, trips the relay coil which then sends 12v power to the fans. This switch breaks ground when coolant reaches 175 degrees and turns the fans off. That way they are not running unless needed and place no draw on the charging system and no parasitic draw on the engine.

This can also be done by purchasing a fan control kit that includes a relay, a temp sensor, a fan control unit and all the wiring needed.

I chose to do mine this way without the fan control kit as relays are cheap at a salvage yard and a fan switch is also cheap. I have boxes full of wire too so I really needed to buy very little.

- The Altima fans are dual fans both with Hi and Lo speed. Each fan motor on this dual fan has two wires so there are four wires for each fan motor. My wire colors differed from another Altima fan diagram I tried to use so you will just have to separate your wires, hook them to a 12v source and figure out which ones are high speed and low speed and which ones are ground.

- Also, if they are hooked up backwards the fan will push instead of pull. They are designed to pull air through the radiator not push it.

- The assembly fits the D21 radiator almost perfectly. Close enough that I needed absolutely no modification to the fan shroud or radiator.

- Temp gauge will continue to use the sending unit it runs off of. Nothing changes there. The ECU sending unit also stays in place.

- The relays I snatched are 30 amp relays and will be used for the low speed fan control. I am getting a 50 amp relay to run the high speed if I ever decide to use it.

- I am wiring this system to turn on the low speed of both fans at 195 degrees and off at 175 degrees.

- The high speed will only come on via a switch that I will mount to the interior dash trim.

- The dash switch I chose was just a cheap 12v toggle from a parts store.
1989 D21 Standard Cab 4x2
2.4L Z24i, 5spd

Last edited by Tally HB; 05-28-2013 at 10:47 PM.
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