Recently my fans were runing all the time. So I changed the coolant temperature sensor and they both would run when the engine gets up to about 230 deg. Latter I changed the thermostat to a 160, and the fan switch to a Hypertech 176-166 switch. After this the primary fan would come on and off at the at the right temperature according to the switch. Just the other day I noticed that the fans are running continuously again. So I changed the coolant temp. sensor because it worked last time but still no change. What could be happening here? If the fanswitch is grounding then the primary fan should be the only one comming on, right?
Any suggestions??

 

Ihave mine rigged to where both of my fans are always on keeps it running better especially since my motor is about to let GO!!!

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TPI 305,
Gutted airboxes,
gutted MAF,
K&N filters,
Corvette Servo.
14.9@93mph

"Speed kills, wanna live forever, drive a Ford."

 

nice reply iroc, didn't have a damn thing to do with his question though. first step is going to be to find out if the computer is requesting them on all the time or if it is a short. if it is the comuter, then it shouldn't be too hard to find the problem, but it would be much easier to narrow down the area of the short too if the computer isn't causing it. that's just where your going to want to start.

 

This is what I have checked:
-Unplugged the AC pressure sensor to make sure it wasn't requesting the fans to come on.
-Unplugged the fan switch.
-Replaced the coolant temp. sensor.
-All relays tested OK.
-No trouble codes
Did all of the above and each time I turned the ignition the fan comes on.
But now only the primary fan runs continuously.
Still can't figure it out.

 

My buddies 87 iroc does the same thing the primary fan runs all the time and we did the same tests as you no codes or no problems with the electrical. I would like to know what the problem is also.

 

My buddy's 87 iroc does the same thing the primary fan runs all the time and we did the same tests as you no codes or no problems with the electrical. I would like to know what the problem is also.

 

Check for voltage on the "in" side of the relay, the wires that actuate the relay. This should be the fan request circut from the ECM. You could also remove the connector from the CTS and see if the fan still runs.

 

Sounds like either the relay itself is stuck (contacts welded together), or the control wire to it is shorted to ground.

 

Like the last post, it sounds like its been grounded somewhere. I know on my car the fan is hooked up to a constant ground so that they will run as soon as the key is turned to on. Id check for that ground....