Replaced the radiator with the help of a friend last week. Noticed in the drive through a few days later the temp over 220°, then realized I turned the AC off. I turned the AC on and the fans did kick in.

I tested it again, ran the motor with AC off and let it get to 235°, fans did not kick on. I checked the connector at the relay, and it seems fine, also the ECTS should be okay since the ECU is getting a temp value. What else should I look for? Fuses and relays seem fine, since the fans do come on with the AC. Any ideas? TIA

 

Suspect the root cause is your PWM solid state "relay" is dead. This device is located behind the front bumper, about 25 bucks at Rock Auto for aftermarket. Your symptom is no variable speed for your fan, only fan off and full on, see attached PDF. In true Chrysler Pacifica factory manual tradition, the explanation is rather stilted, but still kinda makes sense. Unlike some of Chrysler's other tech explanations which make no sense..

 

Does make sense, now that you draw it out. Thanks, already ordered the relay. Much appreciated.

 

 

ETS is fine, temp gauge works as normal. I changed the fan relay behind the bumper and then the car threw a P0480 code. Fans still aren't working like they should with the AC off, but I suspect it's a grounding issue, since I'm having an issue with the horn working intermittently. It's a pretty well documented issue with the IPM on Pacs.

Thanks for the input, though.

 

So, really odd issue resolved itself, sort of.

Decided to replace the upper motor mount (belt drive side of motor) and after reassembling the air box, the fans now come on at about 220 degrees or so. Also, horn works consistently again. From what I figure, the motor leaning to one side must have been pinching a wire somewhere.

Thanks for all the input, all two of you than replied lol

 

Thanks for the update regarding resolution! Hopefully your fans also come on when engine is cool, when the A/C pressure starts to ramp up. With fans off and A/C on, the freon pressure is really high, the PCM is programmed to monitor the pressure via the A/C system pressure sensor located on top of the receiver. PCM should kick on fans when pressure hits 250 psig, the condenser pressure then rapidly drops.

 

Never had an issue with the fans not kicking on with the AC on... just with them kicking on when they're supposed to when the AC isn't running... just always ran the air lol

 

Hey Chris Stephens Coolant temp sensors does what? Tells the pcm what temperature the coolant is. The pcm then tells when to turn the fans on and also tells the cluster what temp the coolant is. So is the coolant temp sensor working correctly?

do a wiggle test with that harness have the fans on ac on see if they cut on or off when you pull on the harness

 

ETS was not the issue, as the temp gauge worked just fine. Also the issue has been resolved already.