2019 Sierra 1500 SLT Cooling Fan Sensor Issue (Resolved)

[BostonBaked]

Hey all. I just wanted to share a recent experience with my 2019 Sierra 1500 SLT that may help some of you. A couple of months ago the check engine light came on and the code pointed to an issue with the cooling fan. All of the fuses were fine and controlling the fan directly showed it was operating just fine. Long story short, it ended up being... a short. Turns out the wiring harness behind the front driver's side wheel well - which connects the computer to the fan - was rubbing against a piece of plastic, enough that it wore away the protective sleeve around the wire harness and eventually wore through the control wire for the fan. Will try to update this post with a picture from the mechanic, but he ended up soldering in a new section of wire, re-sheathing it, and the wrapping the harness in a rubber sleeve. I hadn't seen any similar issues reported for the same code, so just wanted to share in case you run into this, too. He said it took him at least four hours to find the culprit.

[Bikerjon]

Welcome to the forum. Good information! 

 

Thank you for sharing.

[EddDe]

Glad your mechanic was able to track down that short! Here is a service bulletin with known chaffing and pics of some locations.

TSB 21-NA-149

March 2023

Subject: Engine Wire Harness Chafing / ... /

Various DTCs

https://static.nhtsa.gov/odi/tsbs/2023/MC-10232712-0001.pdf

 

[BostonBaked]

On 6/28/2023 at 9:01 PM, EddDe said:

Glad your mechanic was able to track down that short! Here is a service bulletin with known chaffing and pics of some locations.

TSB 21-NA-149

March 2023

Subject: Engine Wire Harness Chafing / ... /

Various DTCs

https://static.nhtsa.gov/odi/tsbs/2023/MC-10232712-0001.pdf

 

Thanks! I believe that second picture on page five is exactly where it was!