Actually I had a similar problem, I had Gaige as my player 2 while I was leveling up Axton to 50 farming The Warrior. It might be a silly thing, but if I had Gaige's gun sights/cross hairs aimed at The Warrior and then launched Deathtrap, he would go attack, but if the gun sights/cross hairs were aimed at no targets (ie. the ground or an empty spot in the sky) then he would do nothing. I tried it again post battle against the volcanic rakks (sp?) and it seemed to work.
If y'all are at the end game bosses with Gaige already, the thing to do is get a life. Sure I'm on a gaming board too but really are you guys need jobs and a social life.
Those guys didn't even played the game , they asked someone else to pump up their characters , they pretty much started using it at level 50. They do not have any experience with the character , experimented nothing and so cannot use it correctly.
Take any level 50 mechro criticism as seriously as intelligent design theories.
Videogame cancer : Perpetual easy mode (AKA USA syndrome), word "main" in fighting games.
What's wrong with powerleveling a character to 50? Once you've played through the story once or even twice the fun is in the gameplay and playing from scratch becomes tedious. If you expect people to level each class from scratch while playing the story you're the delusional one. I for one have leveled from scratch and then powerleveled my other characters. I see no fault in that. The human brain likes repetition, but playing through the exact same story 5 times in a row is a little too much and takes way too much time.
Btw. the reason I fought Verm with Gaige was because I used split screen and loaded her with my main character's game. Storywise she's in Sanctuary (first visit).
Well finished normal playthrough and my DeathTrap attacked Bunker and The Warrior but only with the electric zap move like mentioned above which seems to be his move of choice when it comes to big enemies/bosses. He did goof a little on a Badass Constructor again, just idling in front of it, but that was the only case since Wilhelm for me.
His zapper damage is pretty meh, it can be boosted a little with Catalyst/Zapper series Mods and the electric damage boost skills but seem better to just pump Gaige's own damage and treat DeathTrap's as a bonus.
Like Axton's turrets DeathTrap was good at Rakk clearing duty during the Warrior fight so he wasn't totally useless in that regard even if he actual damage vs. the Warrior was underwhelming, heh.
Verm, Terra, Warrior, Bunker, DT is a complete waste.. in some builds waste of 25+ skill points.. All he does is sit there waiting to use buck up, he refuses to do anything else, even his other attacks I got him.. Bosses act like hes invisible, he does NOT draw aggro anything like the turret.. I have yet to have terra attack him, and only once seen him attack tera himself.. Extremely disappointing
Not trying to be a debby downer but theres something seriously wrong with his AI coding against end game bosses..
Could you share your build? See if getting Laser Attack works.