After noticing that the headlights came on when I turned on the dash switch for the cooling fans I opened up the fan area shrouding and started investigating. In the end I ran 2 10ga wires with 30amp fuses directly from the battery to the front; added 2 30 amp relays to run each fan. the right factory fan was OK but the left one was shot. I bought a SPAL 11 inch high performance puller fan , about 1200 cfm,off the net and did a custom mounting on the radiator. since my car, a '70, had the thermo switch in the bottom of the radiator I wired it to close both relays so both fans would come on at once. the dash switch is also wired the same way. It looked to me like both the dash switch and the thermo switch had full fan power routed thru them, ie no relay; this is NOT a good idea; esp. if you added a larger aftermarket fan that draws more amps; a lot of older cars did this as a way for the manufacturer to save $5 per car. Old switches can have their terminal corode, this causes a smaller contact area for the 'juice' to flow causing more heat to be generated, causing the switch to burn out or short out; your car can burn up, my friend! I also added a separate switch in the bonnet space to cut out the thermo switch which seems to come on low, at about 170 degrees so I then have full manual control. Did you know that engine wear increases dramatically at low operating temps? a 160 thermostat, if you have a thermostat, is great for starting the coolant flowing but you don't want your car to operate at 160. 180 is much better for the motor.
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