My daughter has a 1997 Chrysler Cirrus LX. The car is overheating because the radiator fans will not come on. I checked the fuse and swapped the relays with no change. The temperature gauge is working. I hooked up my obd2 Bluetooth unit and monitored it just to make sure the numbers were changing as expected. At one point the obd2 indicated the coolant was 213 but the dash gauge said it was mid-range.
I tried turning on the a/c to force the fans on, but the compressor does not engage. on more little insight as to what might be going on is that the vent selector knob appears to not do anything. No matter the position it always blows out the defrost vents. However the temperature selector does seem to work allowing hot to really hot air to com out the vents depending on the position.
Ideas?
Because the dash gauge reads other than what the scanner says, I’d bet it’s the coolant temperature sending unit. Because it is reading a lower temp…it doesn’t trigger the fans.
Yosemite
I thought that the dash gauge got its information from the same source as the PCM.
Then based on that, then the a/c not kicking on would be a separate issue?
Does anyone have a drawing of which holes I can jumper across in the relay socket to force the fan to come on just so I can make sure it is not the relay or the wiring between the relay and the fan motor?
A standard ISO relay connects pins 30 and 87 when energized. Look for a schematic on the relay.
Here is a guide; http://rsandas.com/P1_Session_11-3.html
Use a test light to back probe the fan motor connector to check for power to the motor.
The temperature display in the instrument cluster is based on information from the PCM from the coolant temp. sensor. Most Chrysler products will turn the radiator fan on at 210F, some not until 220F.
213F is not alarming, you may allow it to get a little hotter during testing to be sure the PCM is turning on the relay before condemning something.
The HVAC vents are controlled by the Body control module, if a fault is detected it will default to defrost.
All good answers so far. I always disconnect the fans and test them with 12 VDC to see if the fan(s) operate. If they do then I go from there. BTW…I never buy the whole fan assemblies because most makes and models have the fan motors available. It’s a simple swap and saves a lot of money.
I had a Dodge Intrepid that only the defrost worked. The little motor that drives the door had gone bad. Mine was behind the glove box. The part cost me $84 at the dealer. It took me 15 minutes to replace with a long socket extension. Of course I was laying on my back and up under the dash. This was much easier 15 years ago.