Our 16 plate TGX units regularly flash up on screen that a trailer bulb has failed. Could be indicator, tail or brake light, but when you check it, it’s fine. Apparently, according to the MAN man, when you press the light test button and all the lights flash in turn, what you’re supposed to do is: instead of just putting the key in and driving off, pull the indicator stalk towards you (as if you were flashing your high beams). This “marries” the trailer to the unit and stops false errors being displayed.
Edit. Just tried it now whilst waiting to be tipped, seems like you have to push the indicator up (right turn clive) and “end light test” is displayed on dash.
To start the light test / learning function, press the light test button, release, and then pull the indicator stalk up as though you are flashing the main beam. The test will sequence all the lights for a set amount and then stop, if you don’t abort it first.
poleman:
To start the light test / learning function, press the light test button, release, and then pull the indicator stalk up as though you are flashing the main beam. The test will sequence all the lights for a set amount and then stop, if you don’t abort it first.
Nope, definitely right turn. Need to hold it a second though.
Looks like you’re right. Flashing full beam works too. Just have to pull it all the way back so it clicks. Who knew eh? Apart from you two of course! 
Did you ask him why his company builds such ■■■■ trucks?