Cooling fans always on
Cooling fans always on Hey need some help with my 02 ws6 cooling fan . So my car just started doing this but when i start car both coolong fans turn on and run constant until i shut car off. Checked relays and switched them with other relays and same thing. Temp guage reads fine and i tested resistance on temp sensor and seems normal. A/C is off and there is no check engine light on and it does work. Need help what wpuld cause the fans to run constant?
Launching!
Joined: Apr 2010
Posts: 285
Likes: 0
From: Sand Springs, OK
I may be mistaken, but, i believe those cars have two separate coolant sensors. one for the gauge, and the other for the PCM(which controls you fan).
Have you hooked up a diagnostics tool to see what temp the ecm is reading?
Have you hooked up a diagnostics tool to see what temp the ecm is reading?
Teching In
Joined: Apr 2018
Posts: 25
Likes: 1
From: Greensboro, NC
Previous post is right, it doesn’t matter what the resistance of the ECT is, what matters is what voltage the ECM sees. You can backprobe the ECM connector, OR you can look at general scan tool data. If the relay is operating properly my next step is to view data from any module capable of commanding it on. You could be chasing your tail otherwise. If the ECM thinks thinks the defrost is on the cooling fan may kick on.
TECH Fanatic
Joined: Jun 2003
Posts: 1,869
Likes: 99
I read on EFI Live forum that the AC pressure switch can cause fans to run as you describe.
Is the electric plug connection to the pressure switch loose or disconnected? Or perhaps you need a new pressure switch. Inexpensive and easy to remove and replace.
I would also as a test - disconnect the temp sensor on the radiator. Been a long time ago, but I recall I had a similar issue. Went away when I installed a new sensor. Just unplug it and see if it makes a difference.
Is the electric plug connection to the pressure switch loose or disconnected? Or perhaps you need a new pressure switch. Inexpensive and easy to remove and replace.
I would also as a test - disconnect the temp sensor on the radiator. Been a long time ago, but I recall I had a similar issue. Went away when I installed a new sensor. Just unplug it and see if it makes a difference.
Last edited by dlandsvZ28; Apr 9, 2018 at 04:00 PM.
