Cannot find cooling fan relay

check the rad cooling fan motor as this is a common problem with no fan function.

disconnect the cooling fan switch start your engine the fan need start work if don't check your fuse and relay

If the temp goes up at idle and is fine when your driving at highway speeds than the most likley problem is the cooling fans are not working.

the first thing you can do is check to make sure both of the cooling fan fuses are good. you can also check continuity of the cooling fans with an ohm meter.

The cooling fans are turned on by the low and high speed cooling fan relays. you can try swapping the relays.

If the fans still do not come on than you will need a scan tool to diagnose further since the PCM is what controls the fan relays.

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

Check the engine main relay, the radiator fan relay no. 1, 30A CDS and FAN fuses, and the ECT (engine coolant temperature) sensor for proper function. For the ECT, there should be continuity when the engine is cold (200F).

I'm willing to bet you have electric fans on the back side of the radiator that SHOULD kick on when the temp goes up. Those fans have both a fuse AND a relay. FIRST, look for a fuse in the fuse block labeled "fan" (or something of the nature), and check it. If that checks out alright, look in the relay box under the hood for a (1" by 1" square) relay labeled "fan" (or something of the nature). Pull it out and switch it with another relay in another spot. Make sure it is the same relay by comparing the markings on the relay. Turn the car on and watch to see if the cooling fans come on. If they do, you've identified the bad relay.

A simple test would involve disconnecting the fan switch while the fan is on. If the fan then stops the switch has failed. If the fan continues to run remove the relay , if the fan then stops the relay has failed.
Various inputs/outputs at the relay should be confirmed to be 100% certain something strange isn't going on.
Above all be careful of the fan itself , if it's running obviously but if it's not it could start during repair

This is because of the improper circulation of the coolant, if the AC turned on then the engine load will be considerably increase and spoil the thermal switch (which initiate the cooling fan to run). So you better clean the radiator and check the radiator pump, then replace the thermal switch to get the things done.

check cooling fan sensor,which tell the fans to come on

first unplug the cooling fan at its plug and supply 12v to the fan if it doesnt run then replace if it does run follow the power wire to the thermal water switch usualy located at the bottom of the radiator.Use test light/probe to check that you have power into the switch and when engine is hot you should have power both in and out of the switch.if not replace thermal water switch.If that is working you will need to find out why you have no power to the switch.Check that your fuse and relay is working correctly.Sometimes just pulling out the relay and putting back in will make it work due to poor contact.Also try swapping relays with others in the same box near battery to identify if relay is faulty

Most GMs use a relay package to turn on the fans. That is often controlled through a processor package. Very complicated...if yours is one of them. You will need Mitchell's manual or equal to trace this to see if you have all the signals.