Towing elec disconnect alarm?

Sounds like the Newer trucks with the Factory Integrated Brake Controller

Aftermarket....
The Tekonsha Brake Controllers will give you a message on its display not sure about an 'audible' alarm

Not sure if you are talking aftermarket alarms or not, but some of the older cheap alarms were a basic couple of wire hook ups and if it sensed a change in electrical state, for example the car door opening and turning on the dome light, or someone pushing on the brake pedal and the rear lights turn on, or even someone trying to start the car, that would set it off. I'm not familiar with the above posters examples but I had an alarm like the one I mentioned about 20 years ago.

path1 wrote:
Reading a different posting and saw this.....

"My truck alarmed, and I realized the alarm was that the electrical connector between the truck and trailer had disconnected"

I never knew an alarm like that existed. An alarm to let you know power has been lost, what a great idea. Tried googling it up and not much luck. Maybe I'm using wrong name to search.

Where do I get one?

A message is displayed on the trucks info center, typically when equipped with factory integrated trailer brake controller. My 08 Silverado does, my ''13 F-150 did, and my '16 F-150 does.