2016 GMC Sierra 2500HD: Check trailer wiring warning light beep comes on
Common wear/failure (not a recall)
Symptoms
Owners of the 2016 Sierra 2500HD report: check trailer wiring warning light beep comes on. CarComplaints.com lists 1 owner complaints, average mileage 39,000 miles.
NHTSA has 11 owner complaints for the 2016 Sierra 2500HD in this area. Examples:
- NHTSA complaint ODI #11747986 (filed 07/02/2026): “My hmi was "bricked" when onstar pushed an incompatible update when i changed the service plan. while driving the screen has intermittently turned off and on causing temporary unexpected loss of navigation functions, bluetooth connectivity, and use of the ba…”
- NHTSA complaint ODI #11719983 (filed 02/23/2026): “The contact owns a 2016 gmc sierra 2500. the contact stated that the horn was inoperable. the contact became aware of the failure when the horn failed to sound while locking the vehicle with the key fob. upon investigation, the contact discovered that there we…”
Likely causes
Sources do not establish a single root cause; diagnosis is needed. Owner-reported fixes are listed below.
Fix, in plain English
Most common owner-reported solutions on CarComplaints.com: none clearly reported. Check for open recalls and extended warranty coverage with a dealer before paying out of pocket.
DIY difficulty: Moderate
Finding and splicing chewed wiring is doable with a multimeter and patience but can be time-consuming; harness replacement is pro work. (Our assessment.)
Cost
No sourced cost range: get a written quote after diagnosis.
Typical parts (search links, no affiliate codes)
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