If you're tired of drained batteries, hard starts and improper cooling with your aftermarket electric fan, consider making it smarter with Flex-A-Lite's VSC, Variable Speed Control module. The VSC uses a threaded or push-in probe to constantly measure coolant temperature to make adjustments to your electric fan depending on the conditions. The VSC can keep the fan(s) off when you start your vehicle and as the engine heats up, it can turn the fan(s) output to 60 percent. As cooling needs increase, such as for towing or on hot days, the VSC will increase fan(s) output to 80 or 100 percent to bring the coolant temperature down to the desired setting. The VSC can also increase fan output when the AC is turned on. Furthermore, when the engine is shut off, the VSC will automatically cool the engine to the desired pre-set temperature, but will turn off after a short amount of time so it won't drain the battery.