IA 3-speed electric fan conversion harness!

[gmachinz]

This Resistor Harness is designed to convert any single speed fan or fan(s) to act as a 3 speed fan! If you have been fed up with mutliple versions of a PWM fan controller, a controller that is just not stout enough to handle your HO fan or just want a superbly designed fan harness with parts easily available at any parts store or GM dealer should you have a problem...then this is the harness for you!

It's this simple-you have 6 wires to run and need to install (2) GM style temp switches which I can either recommend or supply. I've benchtested this design prior to my actual use of it on my own K10 project and it works flawlessly! Automotive GXL j1128 spec Delphi wiring combined with Tyco commercial grade relays means this is the only fan harness you'll ever need. Eliminate high voltage spikes, excessive fan motor wear and maintain a stable cooling temperature by creating 3 variable speeds for your fan via the innovative resistor design built into the logic control of this setup!

This harness works and single or dual speed fan motors and can run multiple fans. High speed override is limited to 50A with this kit so it can handle anything from a pancake motor design on a typical Spal fan to a robust, high endurance fan motor like that found on a variety of Motorcraft fans including the Lincoln Mark VIII and T-Bird or Crown Victoria.

If you have any questions, let me have em...I guarantee this is the best fan harness you will find! $179.99 is the total price and that includes (2) GM style temp switches to maintain a 185-190 engine temperature no matter how hot is gets outside!

[gmachinz]

I have this same harness available with a trinary switch if anybody is interested also. This means having the AC disengage @ higher speeds which serves to override the relay trigger input once the high side pressure goes down. This eliminates having the fan run at full speed down the highway if it isn't needed to maintain engine cooling. His add-on is an additional $65 feature and includes crimp on connectors with a T fitting, using the 4-wire trinary switch.

[superwade57]

Is there any feedback on this harness? Looks great. How does the speed variance affect the motor life on my fan. Will it work with my 03 grand Cherokee fan? And lastly what temp thermostat do you recommend for the setup with the temp switches you are including?

[gmachinz]

The 03 Jeeps I believe use a single ground triggered relay via PCM controls. You would need to use your existing relay trigger for low speed, then run a stand alone temp switch for medium speed. High speed bypass is accomplished by running the AC lead to the clutch coil of your AC compressor. The kit comes with a 212/202 and 228/218 temp switches. Actual ground triggering can be varied based on where you install the 3/8 NPT switches or you can run your own switches instead. I just finished installing one on this LT1 radiator/fan assembly for a customer. Granted, this is a drop-in kit for a 1978 Z28 but you get the idea.

[superwade57]

I haven't installed the fan yet . It'll be on my 73 swb so would this harness work for me for 2 spd. ? No a/c right now but probably later. Sorry for the confusion. Btw the harness looks great

[gmachinz]

Thank you for the compliments. This harness adapts ANY fan or dual fans to 3 speed operation. If your fan has a high speed terminal, then the harness works of that-if your fan (like a lot Chryslers) requires both positive leads to be connected for series high speed, then you'd simply run both leads together in parallel. The resistor varies speed based on which temp switch controlled relay "drops out"...in other words, as the temperature of the engine increases, a resistored circuit will be reduced based on its control relay contacts opening-so the less resistance, the more voltage goes to the motor thus increasing its speed.

Another way to thinknof this harness is that on low speed, fan will operate at about 7V, at medium speed control voltage goes up to 10V and high speed runs at full 14V+. Since each step is gradual and the starting voltage is so low, inrush current is eliminated and no spiking takes place although I've incorporated these relays with diode suppression. Because there are actual coiled resistors, the start up speed is slow-unexpected surprise when I first designed this fan control harness. With this there simply is no need for aftermarket controllers since this kit uses basic GM resistors and Bosch style commercial grade TYCO relays. With only 6 leads to run, its very easy to wire and as with all of my harnesses it meets or exceeds OEM requirements.

[superwade57]

Pm sent