Trailer Lights flash when not running but connected

[Gutzy]

Not sure where to start with this but assuming maybe it's a GM thing. Hoping someone can explain it. When I am connected to my Ice Castle Fish House and when the truck is not running my running light (I'm assuming) flash on the trailer in a consistent interval. I have never timed it but I would say ever 30 - 60 seconds they will just flash once. obviously if I unplug my trailer lights they won't blink. is there a reasoning behind this? Seems like if I stay plugged in for an extended period of time that it's going to just drain the battery over time. Kind of the last thing I want to happen when sitting on a frozen pond in the North Country. And yeah unplugging is the best thing to do but just found it odd they flash like this and was hoping someone could explain it.

 

Thanks All!

[redwngr]

OM says

 

When a trailer is connected and the vehicle is off, the Trailering App System will
periodically pulse the lighting circuits of the trailer to verify it is still connected. The
trailer lights may periodically flash as a result of this trailer connection detection.

 

These flashes may be more visible in dark ambient light environments.

 

The flashing or flickering lights are a normal condition and the Trailering App System has built-in
protections to prevent the battery from draining.

 

When Theft Alert is enabled, the frequency and pattern of this flashing will change.

 

 

This function has been on GM pickups for quite a few years.

I'm not positive when it started. K2 generation perhap?

 

Edited June 22, 2023 by redwngr

[SVG]

I believe that's a function of the trailer disconnect alarm. Your truck alarm will go off to warn you if someone disconnects your trailer pigtail.

 

The lights flashing is just the truck verifying electrical continuity.

 

If I remember right I had to enable the trailer alarm in my trailer settings on my 21'.

[redwngr]

Theft alert setting:

 

Theft Alert
Theft alert can be set if a trailer is connected and the alert is enabled. When
the trailer is disconnected and the vehicle is off, an alarm will sound.
Touch Theft Alert to turn on/off Theft Alerts for the selected profile.

 

These alerts are based on the Trailer Profile, so the settings for each Trailer Profile must be turned on or off.

 

This setting will be off by default for each Trailer Profile, including the Guest Trailer Profile.

 

A smartphone will receive a notification that the trailer related to the selected Trailer Profile is disconnected from the vehicle,
if the setting is on for the active Trailer Profile, the vehicle has an OnStar or connected service plan and the smartphone number has been added to the account for this notification.

 

If the setting is turned off for a given Trailer Profile, the smartphone will not receive this security notification even if the Trailer Profile is active.

[EddDe]

If trailer theft is turned off, then it is the pulsing to check if trailer is still connected, even when truck is turned off. Trailer lights will flash with my 2020 Silverado 1500 when boat trailer is connected, but I don't see it with travel trailer. GM says to use Curt adaptor 57003, per PIT below. It is dated 6/5/2020, but there may be an update for newer model trucks.

PIT5747 Diagnostic Tip - Trailer Lighting Complaints With Trailering App RPO U1D https://static.nhtsa.gov/odi/tsbs/2020/MC-10178307-9999.pdf

[EddDe]

Here is an update thru year 2022

 

PIT5747B Diagnostic Tip - Trailer Lighting Complaints With Trailering App RPO U1D https://static.nhtsa.gov/odi/tsbs/2022/MC-10208985-9999.pdf

[Gutzy]

Thanks for all the information. I have a 2019 so my old 2012 never did this. just found it interesting. sounds like I will need to play around in the trailing app some more.

 

Thanks again all!