If one were to install a manual override switch to the fan switch system, what is needed? I assume that an extra wire would need to be spliced into each wire/ connection of the radiator fan switch and each end of the extra wires attached to an on/off switch. Would an arrangement like this allow for normal automatic functioning of the OEM switch, yet allow for a manual override when desired? Also, would a relay or fuse need to be installed as well? If so, what rating? Just curious about this--just in case the OEM switch were to ever fail.