This diagram may be used as...
This diagram may be used as reference of wire routing and attachment
A critical component of your engine's support accessories is the cooling system. Gone are the days of a manual belt-driven radiator cooling fan as we have ushered in the more powerful electric fan. Electric fans have been become more popular in recent years due to the fact that they come in a multitude of sizes and capacities. They can be controlled in as many ways and in most cases they are very energy efficient. Fan relays are a critical part of a fan's efficiency because a fan can only run as fast as the amount of power provided to it.
Air conditioning also plays a big part in the cooling of the engine and the cooling of the cabin. The fan needs to run when the engine is at operating temperature as well as when the A/C compressor is in operation. These two instances may not be at the same time. Painless Performance has developed a new fan relay that will allow the fan to operate at a preset engine temperature as well as when the A/C compressor is turned on. This design will allow maximum cooling efficiency of the engine and A/C system. If you don't have A/C, you could also use this second trigger for a manual "On" switch.
 The relay kit comes complete...  The relay kit comes complete with the prewired relay base, terminals, mounting hardware, thermostat, adapter and circuit protection. The thermostats can be ordered in 200/180 degree or 185/170 degree versions. |  Installation is easy. First...  Installation is easy. First mount the relay in a convenient place close to the electric fan. Here, the relay is mounted on the inner fender panel in front of the radiator. This location will allow for the wires to be easily routed to the fan and the A/C switch on the system drier. |  Once the relay base is mounted,...  Once the relay base is mounted, the relay can be installed. The power wires can be routed along the A/C hoses back to the circuit protection and switch. |
 The thermostat wires are routed...  The thermostat wires are routed to the engine, cut to length, and attached to the thermostat. The engine here is a 500ci Cadillac with the thermostat in the manifold behind the water pump. The thermostat comes with an adapter so it can fit a multitude of engine configurations. |  This overhead view of the...  This overhead view of the wiring of the binary switch shows the black (with white stripe) power wire from the A/C thermostat (black with a white stripe) onto one blade on the back of the switch, while the other blade is accepting two wires tied together-the green for the relay and black for the compressor. When the compressor clutch gets a signal to activate, the fan relay also receives a signal to start the fan. |  The power source for the relay...  The power source for the relay comes to the circuit breaker from the Maxi fuse. The circuit breaker is rated at 40 amps as is the relay. As a general rule of thumb, a fan usually needs 1 amp of power for each inch of fan diameter and that figure doubles during fan start up. |