The pop up tv on the 34un is suppose to stop working when you start the engine as jayco must believe it is dangerous to have video playing on the tv as it could distract the driver.
But if your coach doesn't properly turn off the tv when you start the engine then what you need to do is remove the large drawer under this tv and reach up to your right - toward the back of the coach and find the power cable from the tv and make sure it is plugged into the receptacle way back behind the back of the back panel of this drawer area. What likely happened is that this power cord was mistakenly snaked up and out into the dvr shelf and plugged into the receptacle meant for dvr's or satellite receivers. This receptacle is not switched with the ignition and will allow the tv to work even with the engine running and of course Jayco does not want you to be able to watch the tv when on the road for safety reasons And no one would want the tv to work on the road.