2018 Chevrolet Tahoe L83 Symptom: No Sunroof Operation

Adam Technical Support Specialist Minnesota Posted   Latest   Edited  
Case Study
AccuFix
2018 Chevrolet Tahoe LT 5.3L (C L83 Gas) 6-spd (6L80)
The Sunroof Does Not Work At All

This case study was posted on AccuFix by Cody Gaddie. Cody is just one of our highly skilled technicians currently posting on our platform. I hope you enjoy this, and it also helps highlight the great resource AccuFix is offering technicians. To view more cases check out accufix​.​…​.​com/home

Step1. Verified the customer concern, looking at scan data in the BCM under sunroof, noticed none of the switch positions were changing while touching switches. Looking at the diagram, two fuses supply power to the sunroof module. diag​.​net/file/f1v10cu2i…

Step2. Found a blown fuse on driver side fuse box, 10 amp fuse. I installed a new fuse, and the sunroof now works as designed. Checked amperage with an amp clamp and a fused loop. Found when opening and closing the sunroof, the current was only two amps, which is not enough amperage to blow the 10 amp fuse.

diag​.​net/file/f2qke84ro…

diag​.​net/file/f3ufml1jr…

Step3. Next, we need to look at a Power Distribution diagram for fuse 8. Looking at what else is on fuse 8 in the driver-side fuse box, we see the Instrument WLAN Router, DVD player, Mobile Wireless Charger, and sunroof all share the same fuse.

diag​.​net/file/f6epsnkem…

diag​.​net/file/f178i7wsh…

Step4. Looking at the diagram, I see the Mobile Wireless Charger is the easiest thing to access since it is in the lid of the center console. I opened the lid and found the amperage spiked, and my 10 amp fuse blew. I then installed a test light in place of the fuse. There is power on one side of the fuse, and the power goes out to the devices on the other side; with my test light in series, it keeps me from having to replace fuses while I do some testing. When the test light is off, there is no short, but when the test light is lit, there is a short to ground, and the test light becomes our "load" in the circuit. 

diag​.​net/file/f51isk9ip…

Step5. Opening and closing the center console lid, we can see the light is turning on and off; this tells us we have a short to ground inside the lid somewhere.

diag​.​net/file/f791pembl…

diag​.​net/file/f3wmzjpm1…

diag​.​net/file/fhblgfdk3…

Fixing the three wires to the Mobile Charger in the center console lid fixed our sunroof issue.

+4
Helpful
Interesting
Martin Instructor
British Columbia
Martin
 

Good one Adam on behalf of Cody. Somewhat, related is that there can be another issue on the Yukon/Tahoe utilities, that results in an inoperative mobile phone charging pad. It is caused by wiring chafing on the sunroof frame and results in fuse blowing.

+3
Ð Awarded
Helpful
Adam Technical Support Specialist
Minnesota
Adam
 

Thank you Martin I am sure Cody would appreciate that. Also thanks for the additional tip! I can add that tip as a comment to this case on our platform which will add additional value thanks!

+2
Ð Awarded