Well...I did it. I bought a new(used) truck that the PO had put the electric fan conversion in. Coming off of the fan are a bunch of wires. There was also a non-functioning air horn that I took off. There were two wires jammed into the fuse block in the cab and running into the engine compartment to a relay. The only wire I disconnected from the fan was yellow and also went to the relay... I took the relay off assuming that it was there for the air horn. I am unsure how to reconnect it all to get the fan running again. The fan has a blue wire that takes temp from the fins of the radiator. There is a green wire coming off the fan that is not connected to anything. All the larger guage wires remain as they were. Any ideas?

Not knowing what fan you have I can only guess at what wires you have. To properly set up an e-fan you need to run a relay which is triggered from either a temp switch, dash switch, or keyed ignition source. You should rewire the fan so you know what wires are what for next time. I would start by determining the fan's main power source and ground, other wires comming from the fan would be for high and low speed settings, and the temp switch wire. The relay will need to be attatched to the main power feed, grounded to the frame, a fused line to the battery(preferably same saize as the main power feed to the fan), and a trigger switch(from either dash switch/keyed ignition source).

This picture is for lights, but if you replace the "light wires" with "fan main power feed" on the relay you get the idea.

Thank you Snowtoy! Is there a way to determine which color wires are for which function? I am assuming that the fan may be from a GM vehicle...the radiotor is a Harrison GM aluminum and it looks like it was all meant to go together.

Wires...large red directly to battery positive
large blue runs out and back into the fin area from what I can tell
large orange that runs 3 inches to a fuse and then back
two small grey wires run together and are held to the upper radiator hose with a rubber sleeve...looks like it could be some type of sensor on the end?
small green that is tied off with nothing attached
small yellow that WAS attached to the system somehow but I cannot remember how
small black that runs to battery ground

I can handle most things mechanical but have never had to learn electrical...so I am lost! The relay has numbers 85,86,87,30...it is a 30A relay. It seems most of you know what these numbers mean but I could use some help...which is ground, power, etc.?

I'm no expert at wiring/using relays but about those numbers on the bottom of the relay... from memory there should be a diagram etched onto the side of the relay showing the pinout numbers and their function.

The wire colours for aftermarket stuff is pretty much irrelevant. People tend to use what ever wire they have laying around to wire things up. Just look for the main wires coming from the fan. One should be red or white or yellow or something which would be a main power wire and one should be black or brown or some dark colour for ground. Then work your way back from there.

Thank you for your input. I guess I am really basic...I don't understand what the diagram means...

See:
- http://www.bcae1.com/relays.htm

Basic setup is that 85 and 86 are the coil that turns the relay on and off. Two ways that is connected typically, one is that you ground pin 86 (for example) and supply power (12 volts) to pin 85 via some sort of switch (the thermoswitch for example). The other typical connection is that pin 85 is wired to 12 volts and pin 86 is connected to ground via a switch to turn the relay on.

The to supply power to the fan motor, pin 30 is connected to 12 volts and pin 87 is connected to the fan motor and the other side of the fan motor is connected to ground.

That was very helpful 4Crawler! Your whole website has tons of helpful info as well...

My relay has:

85-power from cab ignition switch
86-grounded to fender
87-? does this have to be connected to something?
30-from the website I am going to connect the yellow wire from my fan to this...

The previous set up has the power wire from fan go to a 30A fuse and then connected directly to battery.

The other side of the fan is grounded.

There are two small grey wires that look to be connected to a sensor that is held close to the upper radiator hose via a rubber sleeve

There is a small green wire that goes nowhere...could this be to turn the fan on when the AC is on?

There is a small yellow wire...the one I am trying to figure out...

Before I ruined it...the fan came on automatically and I would like to keep it this way if possible. The yellow wire was the only other wire that was connected. Will this work?

As noted,

85-86 turn the relay on and off. Likely you need the thermo switch for the fan connected in there somehow, as I assume you do not want the fan running all the time.

30-87 are the business end of the relay. One of those two need to hook to the battery (via a fuse) and the other to the fan motor.

http://www.4crawler.com/4x4/CheapTricks/WaterProofing.shtml#FanControl

Thank you 4Crawler...it works now. I did not understand why I had power going to the fan from the battery, power to the relay from the switch and also power to the relay from the battery. But after connecting it all it works and somehow the thermoswitch is wired in. The fan continues to run after I turn the ignition switch off but it turns off after a few minutes. Thank you for your patience...like I warned...very new at relays and electrical in general... <img src="/forums/images/graemlins/cheers.gif" alt="" />