Dont' know if this is a re-post but, i've stumbled across a web-site with some info i thought might be interesting. Oh and sorry for the long post...
I have a 2000 3.2L ES Trep w/190000kms on it. I bought the car without functional A/C (at the time the dealer told me just put a new belt...bull!) so after driving the car for over a year now, i've noticed that once the engine reaches norm temp. and the fans kick in, well they stay kicked in until i either idle for 15 mins or i turn off the engine (yes, even on the highway pressumably)
Anyway, tried changing coolant, bleeding, flushing, shampooing the rad (unrealted p/s leak i thought was baking in the heat on the rad) and then i finally gave up assuming it's the temp. coolant sensor and i would attend to it this summer when i get the chance. Of course my luck, the bearings are all shot on my fans (they have bearings right...and can i replace them?) so now i have that to fix.
What i found related to this long-arse story:
(standard motor parts corp.)
CHRYSLER COOLING FAN
"You may run across a Chrysler LH body car with a cooling fan that runs
continuously, regardless of the engine temperature. Improper diagnosis
may lead you to believe that the PCM is at fault. Before you
replace that PCM, keep this tip in mind. Install your scan tool to the
data link connector. Scan the value displayed as "A/C Pressure". This value is
displayed under the "Engine Controls" section. You may also
find it in the "BCM controls" section if the vehicle has Automatic Temperature Control. This value is supplied to the computer through an A/C
pressure sensor located on the high side pressure line near the
compressor. Since the relationship between pressure and temperature are close in an A/C system, the computer uses this value to track the high side
temperature and turn on the cooling fan when needed. If the temperature is in excess of 235°F., the computer will continually run the fan in an
attempt to cool off or lower the pressure on the high side of the system. In order to verify this value, install you’re A/C gauges to check the actual pressure reading. If the reading on the A/C gauge does not match the
scan tool reading, the sensor should be replaced in order to restore correct fan operation."
Back to my a/c problem, as I said, the guy was a lying scum bag as it wasn't just the belt removed to "conserve gas", but along the lines of: the belt tore off as a result of the idler pully wiggling around because of a shot bearing AND no one noticed because before that happened the a/c suction line developed a pin hole leak caused by the retaining bracket of the line rusting and eating away at the aluminum material. Having said that...my system is in a somewhat "open" state (caused by a literal pin hole sized hole) and there is no pressure what so ever in the system so my question is...could this relate to why my fans are running ALL the time? could the pressure sensor in the a/c line be tricking the PCM into thinking the temp is hot and it's trying to cool?
One more point:
My temp NEVER goes above the middle marking and it switches from high to low speed whenever the engine finally needs cooling (i assume it finally switches to HIGH when the engine really does need cooling, but otherwise always on low speed once at norm. operating temp.)