Pre-trip ???

that only works on older trucks. newer ones don't hold the position anymore.

 

The ones in the Volvo will if you put something a little heavy on it. Did it once to track down an air leak in the service air system on one of our trailers.

 

Don't know what kinda of truck you have but pull the trailer brake all the way down you can check truck and trailer that way.

 

wait.. your supposed to check those?

 

If you have a prostar, turn the ignition on, turn all the lights off (windshield wipers too), & hold the cargo light switch down for 5 seconds. The exterior lights will then cycle through for about 5 minutes...

 

Ask a lot lizard to step on the brake while you look at the rear of your trailer.

 

You dont need stop lights , duh you already know your stopping .

 

it does on my 13 kw t660 also has a bulb check feature. . pulling hand valve down is also good to for checking service side of trl brakes for leaks as a lot of drivers don't do that until they get popped at the scale house.

 

Works on a 2012 Pete 389...

 

The three fellas that said to use a tool to depress the brake pedal down were the winners. Doing it that way you can also listen for air leaks in service brake system (truck and trailer) while you're walking back there to look at the lights. Audible air leaks are a good reason for the DOT to send you to the inspection area instead of telling you to roll on.