I've been diagnosing a 2015 Sonic that has a problem with the radiator fans not coming on. I checked the fan, put power to it and made sure it spun. I checked both radiator fan relays and they both work properly. Both radiator fan fuses are also still good and I have power to one terminal of each fuse. The wire that goes from the fuses to the relays is good. And the wire that goes from the relays to the fan is good. I just can't get the relays to get energized. I don't have a direct ground or positive 12 volt on pins 85 and 86 of either relay either. Are there switches on both sides of the relays? The only thing I've seen actually broken is the cooling fan resistor but I don't think that would stop the relays from energizing since it's wired directly to the fan.

If anyone has a diagram for the fan wiring it would be very helpful. Unfortunately the only solution I can come up with is a broken wire somewhere or a switch isn't working. If anyone has any ideas please let me know.
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thanks!

 

Try charm.li

 

Thanks! I found a wiring diagram on there for a 2013 and it says I should have power on pin 86 from some 20 amp fuse and the ECM switches the ground on pin 85. I assume a broken wire in the fuse box. I'll have to look into it tomorrow and update if that's it!

 

You should be measuring 12V on both terminals of the fuses right? If not then the fuses are blown.

Power to energize the relays comes from the 20A fuse, not the fan fuses. So check that too.
There should be 12V on pins 86 anytime the ignition is on.

Looks like there's an ignition relay

 

Took apart the top of the fuse box and cleaned it out then I got power back on pin 86. I got nervous testing it because I guess the ECM turns the fan on when the coolant is 227 degrees haha.