2017 C7 Fans not working
Thread Starter
Racer
Joined: Feb 2008
Posts: 438
Likes: 141
From: Elmira Ontario
2017 C7 Fans not working
I have a 2017 stingray fans will not some on during normal operation but can be commanded on. Swapped fan with a known good one no difference. Went over the wiring, all good. Circuit is power, ground, and a pwm signal from the ecm. Checked resistance between fan and pcm all ok. Checked the resistance of every wire to every sensor responsible for turning the fan on (coolant temp, oil temp and ac pressure). All ok. Sensor data is accurate. In the scan tool you can see the command signal changing but the fan does nothing. Just replaced the ecu and when I did a heat cycle the fan came on so I called it good but later they weren’t working again.
Has anyone had a similar instance?
Has anyone had a similar instance?
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,626
Likes: 4,069
From: Cape Coral, Florida
Resistance checking really isn’t the correct way to check the cooling fan circuit…if you can check the PWM signal wire with the scan tool and the fan is still inop you should be checking the fan supply voltage at the module and since it’s PWM you might see the voltage change with a DVOM as you change the duty cycle with the scan tool…a graphing multimeter or labscope is the preferred method to check a PWM signal since a DVOM is too slow to see the change !!…did you check the Low Reference (ground) at the module ??…do you know the proper way to check a ground ??…resistance checks are NOT the correct way !!…actually the ONLY resistance checks I do are the terminating resistors on a CAN bus…that’s it !!
