Starter engages when brake pedal is pressed and Right signal is on

[LITE]

What is wrong with my 2014 Hino 268 when the starter engages when the brake is pressed or the right signal is on? It engages both while the truck is running and when the truck is turned off.

 

[greasytshirt]

There is almost certainly water in the junction box behind the air filter. The connectors need to be opened, dried, corroded terminals fixed, and the source of water needs to be found and addressed. If the cover is installed wrong this can happen. Windshield gasket leaks are also likely. Pull up the passenger side carpet and see if the insulation layer is wet.

I've run into a very similar problem. With the truck running and foot on the brake the starter engages.