Aux fan

[Z06killinSBF]

I plan on running an aux cooling fan to use for my A/C. Does anyone make a switching assy. I can use to power the fan when I turn my A/C on? Car in ? is a 66' Mustang with a Vintage Air kit.

[CarlC]

Why not use a simple 30-amp relay using the A/C clutch wire to activate it? Simple, and costs less than $10.

[gmachinz]

What type of aux. fan are you going to use? Amp draw can be high depending when on 100% via a relay. What have you done to upgrade the charging system?

[Z06killinSBF]

I havent choose a fan yet. I will be upgrading to a 140 amp alt soon.

[MonzaRacer]

When you install it all you really need to do is have a dual relay set up and have the power side of the AC fan relay tie into the power feed if you want it to run if car gets hot, then wire in a cooling fan switch such as the ones for the older GM cooling fans as Hypertech and other still sell them.
wire it up so the fan can run till the negien gets cool enough to shut off(gennerally it will go off in 10 minutes or less.
Now remember the relays are controled either by power or ground but the power to them should be straight from a junction block/battery connection.
The regualr cooling fan switch will ground the RELAY pull in side and the AC fan relay will be grounded and gain power from when your AC turns on, laos look around for a throttle kicker if you dont have EFI so it can be wired to give your engien a few extra rpms when the AC is on.
I like to use a 2 stage kicker so it is used to set base idle and then when the AC is activated it jumps the rpms up to a stable idle with extra load.
The power to both relays can be drawn fro mthe same heavy(10ga to 8 ga) wire nad feed to fan with at least an 10 guage wire and make sure your fan ground is to a solid ground(I prefer to run it right back to a ground junction block or battery my self). Whe nthe AC relay power on it wont hurt the other relay and also look at your relays as they will have a diagram picture on the relay and look at the line across the pullin side. if it has an electrical pic of a diode(rectangular box with line at one end and an arrow pointing to that line) dont buy it as it HAS to be wire properly or you can spike the electrical system. simply use relays with a squiggly line in there as it is suppressed by a resitor rather than a diode.Diodes are one way gates and resistors can work either way making less headaches for you.
I actually prefer the oval GM type and get them from the salvage yards with relays plugs and hangers.
The gray connectors are continuos on (like fog lights,AC,fans) but if it has a black connector it will be able to be wired as powered on or powered off relay.
I will try to take a few pics and demonstraight what I mean.
PM me if you are confused.
Lee Abel
AFTERMARKET PERFORMANCE