just remove all power from your aftermarket system to eliminate it as the problem with your D not starting. I would disconnect the power from the power source side to be 100% sure your aftermarket stereo system has no juice going to it. If durango starts up, then you know where the problem lies, if it does not start, it is not your stereo system.

As far as the alarm system goes, I do not know if the OEM factory stereo would cause it problems if it were replaced with an aftermarket. I would say no as users in this community would have spoke out about it.

 

it sounds like he does not have the D to work on... it's at the dealer.

I would wait until you get it back before speculating on what could be wrong. adding a stereo wont kill a truck unless you have a dead short, then you'll have lots of smoke.

 

what could kill power to the alarm but not the stereo?

 

may have found the problem finally got around to taking panel off under the steering wheel after market security system was install by some one who was not very intelligent alot of wiring doesnt go anywhere like the alarm isnt even getting power?

 

after being 99% sure it was the security system i found that it was an ignition coil and the d is running again but back in the shop for ball joints