Ditch that clutch fan and upgrade to dual electric fans!
An e-fan upgrade will decrease the load on the engine and water pump that will result in increase HP and throttle response. In addition, an e-fan harness will draw more air across the radiator in stop and go traffic and at idle, which will result in cooler engine temps and cooler AC temperatures in the cab.
We offer two types of e-fan harnesses, 1 pin and 2 pin. If you’re deciding on which e-fans to choose, your options are the f-body e-fan assembly and the ’05+ truck e-fan assembly. Keep in mind the use of the vehicle, amount of weight being towed and cost of upgrade. You can order your harness with a choice of efan connector depending on which electric fans you are using. Please keep reading to see which harness is the best one for your application.
The e-fan option 1 is for trucks/suv that are equipped with a 34″ radiator. This radiator is factory installed in most GMT800 2005+ and 2008+ GM trucks/suv and some heavy duty vehicles. Generally speaking and relating to what is typically accepted on forums, it’s the radiator that is installed on all GMT900 1/2 ton trucks/suv (named nnbs on the internet). You can change out the radiator to the larger 34″ if you would prefer the added cooling it will offer.
The e-fan option 2 is for GMT800 99-07 trucks/suv (cbs) equipped with the 28″ radiator. This radiator is in most 1/2 ton GM trucks from 99-07. The radiator is 28″ wide and will only accept the f-body (99-02 camaro and trans am) e-fan assembly. The e-fan harness is equipped with f-body (ls1) e-fan connectors and will plug directly into the f-body fans. Pics are supplied in each type of e-fan assembly to assist in picking the correct e-fan harness.
The PCM/ECM/ECU must be programmed in order for the harness to work! You will be able to an add this feature to your order before check out.
Additional information regarding one and two pin harneses.
This explanation is why a one pcm pin harness and a two pin pcm harness. (1pin / 2pin) is offered.
– The 99-02 GMT800 (cbs) trucks/suv PCM do not support a high speed AC stage 2 activation. This means the e-fans will activate on low speed based on engine coolant temp (ect) and low ac line pressure. The alternative to high speed e-fan activation ( both e-fans on high speed) is to activate the e-fan relay when the AC clutch is engaged. This is required to maintain acceptable AC pressures during low speed mph.
– The reason why this is implemented is due to the fact that the 99-02 trucks/suv are not equipped with a tertiary high pressure ac sensor. The PCM does not register AC high pressure, which means the PCM cannot activate high speed when AC pressures exceed a certain value. We do offer an upgrade for the 99-02 trucks that will allow the use of an AC high pressure switch. This means your e-fan operation will function just like a 2005+ PCM. (Please email us directly if you are interested in this upgrade.
Note: The HD GM trucks/suv clutch fan will pull/draw more air while towing vs electric fans.
If the vehicle is used for heavy towing then we do not recommend the use of an electric fan unless tow weight is light.