Neither Fan Turning? is that normal in summer?

[sad-lumina-owner]

My /94 3.4 DOHC v6 has two fans infront of the engine rad.

Neither one seems to turn alot of the time. I've only seen one turning, the one on the passenger side.

I noticed you can't reverse the connections and switch the fans' power supplies/control connections, because the designers have reversed the plugs to each fan, so a left can't plug into a right connector and vice versa.

This leaves me with no way to test to see if just one fan is burned out, by swapping them.

Does anyone know what a 'normal' duty cycle is for these fans? Their idleness makes me nervous. The engine does seem to run hot.

Perhaps the temp sensor (where is that anyway?) is disconnected or broken...

Any ideas?

[Blue Bowtie]

The factory settings for fan operation are relatively high. The primary cooling fan should turn on when the coolant temperature is at about 226ºF and back off once the coolant temperature drops to 215ºF. The cooling fan should also operate if the air conditioning compressor is running. Both fans should turn off if the vehicle speed is above 32-34 MPH.

Later model years use the actual refrigerant system pressure to control the fan(s), but I believe your model is more direct.

You can connect a bi-directional scanner and command the fans to turn on via the scanner if you suspect a control problem.

[sad-lumina-owner]

Originally Posted by Blue Bowtie

The factory settings for fan operation are relatively high. The primary cooling fan should turn on when the coolant temperature is at about 226ºF and back off once the coolant temperature drops to 215ºF. The cooling fan should also operate if the air conditioning compressor is running. Both fans should turn off if the vehicle speed is above 32-34 MPH.

Later model years use the actual refrigerant system pressure to control the fan(s), but I believe your model is more direct.

You can connect a bi-directional scanner and command the fans to turn on via the scanner if you suspect a control problem.

Thanks for the info, BlueBowtie!

This may in part explain the fan behaviour. I think I'd like something in the cab like an LED or something to tell me when they are running just to get a feel for the operation, maybe along with a coolant temp readout (one that accurately works).

[4x4 blazerguy]

Our 93 3.1 V-6 the fans only work when in traffic at slow speeds & only one comes on. When I run the A/C both operate. Even in Bullhead City AZ in summer 120+ degrees the fans only worked with A/C & one would work without A/C only in stop & go traffic. On the road they seldom ever come on.

[sad-lumina-owner]

Originally Posted by 4x4 blazerguy

Our 93 3.1 V-6 the fans only work when in traffic at slow speeds & only one comes on. When I run the A/C both operate. Even in Bullhead City AZ in summer 120+ degrees the fans only worked with A/C & one would work without A/C only in stop & go traffic. On the road they seldom ever come on.

Thanks for this:

I wonder if since I removed the AC, I should hook up the (2nd) fan differently, so that it actually functions. Perhaps the two relays can be shorted (wired in parallel) so that instead of one fan on, they both come on when you need to cool down (that would be twice as fast at cooling and they would still shut off when the temp was restored...)

Now I wonder if the relay(s) can take the doubled current load from two fans. If not, maybe they can be paralleled. If so, one relay could be a spare!