Trouble with cooling fans
Thread Starter
Heel & Toe
Joined: Mar 2008
Posts: 18
Likes: 0
Trouble with cooling fans
I changed one of the relays for the cooling fans and now have 1 cooling fan working. Can someone tell me which fan is the main cooling fan that is activated by the temperature of the motor and which fan is activated by use of the air conditioning. I have the driver's side fan on.
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
Depends on Year. If both fans are behind the radiator ('90 up), both are controlled by the ECM/PCM based on inputs from the Coolant Temp Sensor (non a/c), or the a/c pressure switch (a/c). If you have a Pusher in front of the Condensor and a Sucker behind the Radiator ('89 and below), only the Sucker is controlled by the ECM based on the inputs from the Coolant Temp Sensor (non a/c) or the fan switch on the a/c high pressure line (a/c). The Pusher operates on a temp switch which is screwed into the cylinder head. An option for these Years, it should rarely if ever come on and plenty of C4's cooled just as well with the single fan. And if you think you need it working to keep your coolant temps right, you don't - or there's a big problem with something else and it won't matter how many fans you have running.
Mine's a 92 with the same.
Le Mans Master
Joined: Jun 2006
Posts: 5,642
Likes: 5
From: One day you're a Comet...the next day you're dust... Arkansas
I changed one of the relays for the cooling fans and now have 1 cooling fan working. Can someone tell me which fan is the main cooling fan that is activated by the temperature of the motor and which fan is activated by use of the air conditioning. I have the driver's side fan on.
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
Primary driver's side should be around 226 for non a/c - secondary will be north of that number. If you want to see what it is, you'll need to hook up a scanner so that you can see the Coolant Temp Sensor Signal OR, Primary should be coming on when the A/C Pressure Sensor Signal is something around 200 PSI and usually the secondary is grounded with a signal of 230 PSI. That signal can also be read with a Scanner or a Manifold Gage Set. Doing anything else is a guess; ie, you don't know if you have a problem until you see the sensor signals while observing the fans.
