Hi,

I have a question that I'm a bit puzzled with.
Yesterday I was flushing the radiator several times and the van was running for well over an hour. During this time not even a single time the radiator fan turned on. I was adding a cold water all the times and monitored the temp gauge. So, after all, the van reached the standard operating temperature but as I said no running fan.
My question is - when should the fan turn on and off?
Before that, when driving I felt the fan turning when the AC was running. Should I check the ECT sensor, fan relay and fan motor? Is there any simple way to turn the fan or system on before it will reach the X temperature?
I have a leaking water pump and was wondered if the heat / failed radiator fan had any contribution to this issue.

Thanks for all your comments / suggestions.

 

The radiator fan turns on - coolant temp = 220 F, A/C pressure = 250 psi, Trans = 204F

The radiator fan turns off- coolant temp = 214 F, A/C pressure = 248 psi, Trans = 192 F

 

What's the easiest way to test the fan and relay?
Thanks

 

Turn the A/C on. The fan should spin right away. That proves the fan motor and relay are good. Not absolutely sure that proves the PCM is good but it does prove the PCM will control the relay if the A/C is turned on.

 

Thanks Cougar41 .. (as always)!
That is what I did and yes it works.

 

Hi all, I'm a newbie here but have the same van and similar questions. Hope it's ok to throw a few seemingly related questions on this thread... My question is related to A/C system cooling fan. The fan runs sometimes, definitely not turning on very soon after when the A/C is turned on. Although, i have seen and heard it turn on much later.

I do get nice cool air from the AC when the vehicle is moving so I know the fan isn't always running when it should. Where should I look first? Relay? Also, are the two cooling fans on the radiator independent and for different purposes, or should they run together?

Thx!

Dan

 

The fan only runs at certain pressures, do you have gauges connected to see when it comes on and goes off?

 

Ok Just put the gauges on and it and the fan did kick on at about 270psi. (My cheap gauges may be off) Both fans are working. It quickly dropped the pressure down to around 110psi and fans stayed on for at least 4 mins. It started pouring out so I didn't run it any longer to see when they would shut off.

Tizzy1- those numbers you mentioned describe an A/C pressure for on and off of the fans as being only 2lbs difference, that sounds like rather small window...was that a typo? Should my fans have shut off at 110psi, or do they cycle for a minimum time period?

 

At 300 psi, the fans ramp from a duty cycle of 30% to 99%. 248 psi is where they ramp from 99% back down to 30%. Full off psi is not listed.