No high speed cooling fans?

[CTUBS8732]

I’m having this exact same issue. I just replaced the whole cooling fan relay fuse block with a fresh one cause the original had burnt prong ports. Thought I had solved the issue when I found out the ground was mounted in a bad spot due to shotty repair by body guy so I regrounded to a better spot.

Now I have your issue going on at the moment and noticed the bottom left relay on the bottom left port is burnt.

Fans magically turned on high mode then never did it again. I’m stumped on this one.

 

[Doubeleive]

I’m having this exact same issue. I just replaced the whole cooling fan relay fuse block with a fresh one cause the original had burnt prong ports. Thought I had solved the issue when I found out the ground was mounted in a bad spot due to shotty repair by body guy so I regrounded to a better spot.

Now I have your issue going on at the moment and noticed the bottom left relay on the bottom left port is burnt.

Fans magically turned on high mode then never did it again. I’m stumped on this one.

this is a different generation, everything is different fan wise. my 2012 fans go on high and you can hear them well, never hear the fans on my 18
I assume you are talking about the nbs, you might want to inspect the fan motors and harness connectors and see how they look I had one that started to short and melted the connector a little bit and quit working until I bumped the harness. replaced the motor and harness connector and they work good again.

 

[CTUBS8732]

Mines is 2005 Tahoe. Usually the fans are on high as soon as I start the truck with the AC on. Now high mode never kicks in even if the truck is idling for an hour. It ain’t overheating but also ain’t no cold air coming out the vents, just cooler than outside air. Refrigerant level is good.

 

[CTUBS8732]

When driving it’s cold

 

[CTUBS8732]

Changed temp sensor now only one fan spins in low mode and the other kinda spins. Prior to replacing, both wouldnapin in low mode. Only rear ac blowing how it should. Refrigerant is good. I'm stuck in a rut with this one