Need help 15 Tahoe fan stay on after turning it off.

[Javier Hernandez]

Got a 2015 Tahoe the electric fans stay on after I cut the truck off. I changed out the thermostat and the temp sensor, but I can’t figure out the problem, now the heater blows cold air and the air blows hot air I’m lost please need help TIA

 

[OR VietVet]

Here is a thread you might want to read: https://www.tahoeyukonforum.com/threads/rad-fans-run-with-no-key-on-cold-engine.123822/

Not the same years but there may be info in there to help.

By the way, welcome to the forum from Oregon

 

[Javier Hernandez]

Here is a thread you might want to read: https://www.tahoeyukonforum.com/threads/rad-fans-run-with-no-key-on-cold-engine.123822/

Not the same years but there may be info in there to help.

By the way, welcome to the forum from Oregon

Thank you ! Sir

 

[Masonson]

Got a 2015 Tahoe the electric fans stay on after I cut the truck off. I changed out the thermostat and the temp sensor, but I can’t figure out the problem, now the heater blows cold air and the air blows hot air I’m lost please need help TIA

My wife just got home from work and she's having this exact issue for the first time.

2015 Yukon Denali, Coolant temp is pegged at 160, 45 degrees outside, trans temp is not hot either.

 

[OR VietVet]

My wife just got home from work and she's having this exact issue for the first time.

2015 Yukon Denali, Coolant temp is pegged at 160, 45 degrees outside, trans temp is not hot either.

Read this thread to see if can help. Not the same years but may have some info you can use.

https://www.tahoeyukonforum.com/threads/rad-fans-run-with-no-key-on-cold-engine.123822/

 

[Masonson]

So I disconnected the battery, let it sit for 20 min.

Reconnected battery and started the truck up, coolant temp came up from 160 and the fan did not come on. Im thinking the coolant temp sensor had a freakout and the electric fans just fail-safe turned on. We'll see.

 

[Javier Hernandez]

So I disconnected the battery, let it sit for 20 min.

Reconnected battery and started the truck up, coolant temp came up from 160 and the fan did not come on. Im thinking the coolant temp sensor had a freakout and the electric fans just fail-safe turned on. We'll see.

So I disconnected the battery, let it sit for 20 min.

Reconnected battery and started the truck up, coolant temp came up from 160 and the fan did not come on. Im thinking the coolant temp sensor had a freakout and the electric fans just fail-safe turned on. We'll see.

I did the same thing I disconnected the battery and the temp went up to normal and the fans worked the way they should but it started again and I don’t know what it could be

 

[Masonson]

I did the same thing I disconnected the battery and the temp went up to normal and the fans worked the way they should but it started again and I don’t know what it could be

Have you found anything out? I replaced the coolant temp sensor, it worked for a couple months but started again.

 

[sb38646]

Have you found anything out? I replaced the coolant temp sensor, it worked for a couple months but started again.

Same replaced sensor but still the problem persists. Still resetting battery when it occurs

 

[Prospect62]

Have you tried replacing the thermostat?

 

[MD-Wood]

I'm finding several electrical issues popping up on my Wifes 2015 Tahoe. I have worked through all of them to date and find Most issues come down to the electrical connectors at the plugs. I have also found issues with the crimped connectors on alot of the heavy positive and negative cables. To date I have fixed Dash going out, center console going out, fans running on High, seat sensors airbag, Battery negative cable crimps, positive cable crimps, alternator harness crimps and connectors, suspension harness connectors and a few more I have forgotten about.
All have been fixed the same way, checking the connectors, continuity testing terminal to terminal for shorts, cleaning them with WD, gently brushing the spades, a small amount of dielectric grease, plug and unplug them a dozen times. Few and far between is a recrimp on the terminal ends, it is much more common on 14gauge and up, the copper expands and contracts more and should be checked. It seems to work.