Cooling fan trick
Thread Starter
Burning Brakes
Joined: Oct 2004
Posts: 898
Likes: 1
From: Pearland Texas
Cooling fan trick
I've exhausted myself searching for thread containing a post with a trick to read the temp programmed to turn on the fan. You use the A/C up and down to find the setting. Can somebody help. 
Intermediate
Joined: Aug 2007
Posts: 40
Likes: 0
From: Raleigh NC
I don't think you can get the temp when the ECM will turn on the fans. But you can get the degree celcius reading that the ECM uses to monitor. The sequence is: (copied from a previous thread)
Hold down both the up and down arrows on the heater fan control for 10-15 seconds. The heater fan control display should go to 00 after you've held both buttons down long enough. Once it says 00, use the up arrow to cycle to number 16, then press the button with the picture of the fan on it. That should show you what the ECM is seeing for coolant temperature, in degrees C. The computer uses a different sensor than the dash mounted gauge, and the dash mounted gauge (at least the one in my 91) isn't very accurate.
Hold down both the up and down arrows on the heater fan control for 10-15 seconds. The heater fan control display should go to 00 after you've held both buttons down long enough. Once it says 00, use the up arrow to cycle to number 16, then press the button with the picture of the fan on it. That should show you what the ECM is seeing for coolant temperature, in degrees C. The computer uses a different sensor than the dash mounted gauge, and the dash mounted gauge (at least the one in my 91) isn't very accurate.
Thread Starter
Burning Brakes
Joined: Oct 2004
Posts: 898
Likes: 1
From: Pearland Texas
I don't think you can get the temp when the ECM will turn on the fans. But you can get the degree celcius reading that the ECM uses to monitor. The sequence is: (copied from a previous thread)
Hold down both the up and down arrows on the heater fan control for 10-15 seconds. The heater fan control display should go to 00 after you've held both buttons down long enough. Once it says 00, use the up arrow to cycle to number 16, then press the button with the picture of the fan on it. That should show you what the ECM is seeing for coolant temperature, in degrees C. The computer uses a different sensor than the dash mounted gauge, and the dash mounted gauge (at least the one in my 91) isn't very accurate.
Hold down both the up and down arrows on the heater fan control for 10-15 seconds. The heater fan control display should go to 00 after you've held both buttons down long enough. Once it says 00, use the up arrow to cycle to number 16, then press the button with the picture of the fan on it. That should show you what the ECM is seeing for coolant temperature, in degrees C. The computer uses a different sensor than the dash mounted gauge, and the dash mounted gauge (at least the one in my 91) isn't very accurate.
Drifting
Joined: May 2003
Posts: 1,979
Likes: 48
From: Lakeport CA
Here is the link to the full set of diagnostics avail. that way:
http://www.idavette.net/tech/c4diag.htm
http://www.idavette.net/tech/c4diag.htm
