2012 Dodge Caravan 3.6 VVT cooling fan problems

I have a 2012 Dodge caravan 3.6 VVT that the cooling fan will not work with A/C on. I removed the fan relay and and bypassed the control with my u-activate tool and the fan works fine. I then tried to turn the fan on with a scan tool. It will toggle on and off just fine but it will not turn on when you try to turn on the duty cycle with the scan tool. no matter what percentage you try the scan tool aborts the test and says request out of range. I have tried the test with the fan unplugged and with a light bulb subsituted for the load. Any help is much apriciated, thanks.

Is it throwing any codes in any module?

Maybe it's the fan resistor. See if dark blue /dark green wire gets power with the AC on.

B2304 Stored wiper park switch input ciricut low.(stuck Low)
P0691 Stored Cooling fan 1 control circuit low.
P0693 Stored cooling fan 2 control circuit low.
I believe i set the cooling circuit codes by unpluging things

when I first started looking at this problem the cooling fan resistor was cracked wide open near where the connector is. I replaced it with a new one from dodge. I can energize the circuit from the low speed relay in the Tipm so I know it is working.

By the way, thanks for the wiring diagram that is a big help

On the 2.8L diesels the cooling fan is pulse width modulated so maybe your scan tool was having an identity crisis, at least for that function.

Well you've tested the fans bidirectionally and they work, so we need to focus on inputs. After leaving the car off for a long time, are your IAT, ECT, ambient air temp, trans temp reporting close to the same temperature? Within 5 degrees of each other?

What about your AC pressure transducer? I'm reading that the cooling fan will be commanded on when the ac pressure rises above 240 psi.

This is very good information. I noticed that the high side pressure scan data seemed low to me. It started out at about 180psi and did eventually get up over 225 but it may of never reached 240. This is giving me more direction. I will not get back to this until monday but i will keep you posted with what I find out. Thank you very much.

patrickw wrote: I can energize the circuit from the low speed relay in the Tipm so I know it is working.

For clarification did you energize it bidirectionally with the scan tool? Just want to be sure you can get two fan speeds to work with ONLY your scanner.

patrickw wrote: P0691 Stored Cooling fan 1 control circuit low.
P0693 Stored cooling fan 2 control circuit low.
I believe i set the cooling circuit codes by unpluging things

Those can certainly be set when the relay is removed but make sure and start fresh - clear the codes, cycle key and recheck the codes. Turn on ac and recheck for codes again.

I feel like I ran into something similar on a routan (same vehicle) and looking in service data, the logic to turn the fan on seemed odd and related to AC pressure. I know that charging the system fixed it because the pressure was low but I can't remember the exact symptoms.

I'm pretty sure the complaint was no AC, and I saw that the fans weren't turning on and started heading in that direction, then saw service info on it.

I don't have the info pulled up but I may be able to get to it in a bit to see if it matches up with my memory.


Nissan Technician

I did turn the fan on and off with the scan tool and made it toggle on and off. only high speed. got kicked out of the test when i tried to PWM the fan, the test was aborted no matter what %

These parameters need to be met for the fans to come on. Your AC pressure is too low.

Thanks for all of the help. Charging the A/C system solved the fan issue. The fan problem was a result of the low pressure in the system. It is fun to watch a dog chase his tail, not so much fun to chase your own tail. Thanks again for the help.

No problem. I know what you mean. I chased my tail on this one too.

Nissan Technician

I had the same issue with the fans not coming on. My scanner can cycle the fans on ok. I am surprised these caravans do not have the cooling fan running when the compressor engages. They seem to have a fairly high pressure for the fans to turn on.

Another questions related to this. Should the compressor cycle on and off? Or does it run constant when the a/c switch is on? I suppose that since my pressure is not at the proper charge, it's going to keep running.

Update. August 14, 2020
I have diagnosed everything else with this system in the past few months. I had to conclude that I just didn't have enough gas in the system. I don't have a scale to weight what amount I put in. That's my next purchase. I go with the temperature and pressure readings to determine when I have the correct charge. I attached the manifold set last night and watched the pressure readings. These readings are at idle. Low was sitting around 35 psi. High would climb to about 240 and higher but no fan engage. I topped up the gas a bit and the low speed fan turned on. Closed off the gas. Let it run while I watched the center vent temperature. Topped it a bit more. With the ambient temp at 80 deg F, the vent temp was close to 40 deg F. Fan engages now at about 270 psi. Low is sitting at 40 psi.
Out and about today for work, sitting idling at a job site. Ahh nice and cool and the low speed fan is running.