That is true. Whatever the compressor does; the fan is going to do the same.

 

WHY NOT INTERSEPT THE HOT WIRE TO THE FANS AND PUT A SWITCH ON IT. THAT WAY YOU CAN TOGGLE THE FANS OFF WHEN THEY DONT NEED TO CYCLE ON AND OFF.

 

John - Is it bad for the fans not to come on with the A/C? I saw in another thread about the VSC that it might be bad.

I've had my VSC wired up without the A/C relay hooked up and haven't had any problems outta the A/C compressor/system but, I don't want to be recommending something that could potentially damage the A/C system.

When driving slow/idling with the A/C on the fans are on anyway pretty much and when your cruising down the highway do they really need to be on with the A/C? It seems that just the air going through the radiator/condenser is plenty to keep things cool.

 

It can be a bad situation if the engine is not up to temp and you have the A/C on, and you're in stop and go traffic. With the A/C on and the fan(s) off, the A/C head pressure can get too high.

It may not be a big issue on the trucks though. I haven't looked at the diagrams that close, but the trucks may cycle the compressor off and on to maintain head pressure; where the cars do it by turning the fans on to keep the pressure down.

Maybe the temperature input is all you guys need to worry about for fan control. After all, there isn't anything to engage the stock mechanical fan based on A/C on or off!