Installing Spal Dual Fan....

It depends.
Do you want it to go from no fans to both fans?

Does each fan have two speeds and do you want to utilize each?

Do you want to use one fan in traffic and wire one to the A/C circuit for automatic fan start-up when A/C is on?

Good luck.

I run the dual SPAL set up. You can wire them together through one relay/toggle if you like. But I can tell you -- it's gonna REALLY hit the alternator/battery when you turn them both on -- personal experience. I experimented with all kinds of set ups -- running them together, running them separately -- on different temp switches, etc.

Then I finally wised up and bought a DC controller. Even for a cruiser I HIGHLY recommend you leave the archaic and inefficienct world of 75A relays behind and buy a variable current/speed controller. MUCH better way to run these fans.

If you choose not to, I'd at least buy 2 relays and wire them up on separate toggles. Hit one fan -- if that won't cool it then bring the other one on. That minimizes wear/tear on the electrical system.

Here's a link with some info on my DC install driving the SPAL fans...

http://www.etnracing.com/pages/Tech/FanControl.htm

Love to cj - but I'm out of town on business with no access to my old receipts. I bought the kit -- and I let Brian know my battery had been relocated to the trunk so the wiring he provided me had a longer hot lead to reach the battery at the back of the car. Also a filter to go between the ground/hot leads on the controller to eliminate any problems with induced voltage spikes/drops when the starter drops off the system after cranking.

As I said before - I'm out of town. But his prices are clearly shown at the website I believe. Go here http://www.dccontrol.com/ and click on 'fans and kits' -- look for the FK35. Seems it was around $109. That's controller and everything you should need to wire it up.