alarm coming on by itself, the radio turns on, all the interior lights turn on?

I took my vehicle listed above to get a Durangoput on in order to pass inspection in early August, now last week my check engine light came on and everything started happening, the alarm coming on by itself, the radio comes on, all the interior lights comes on and the lights in the dash started flashing... my question is it possible that the sensor that was put on caused these problems, because none of this was happening beforehand, and I only got the sensor to pass inspection ...*ps* they put the sensor on had to drive a certain speed and number of miles in order for the check engine light to got out, it never went out after taking it back to the mechanic they took it in the shop and when it came out the check engine light was off.... and this is about 3 weeks before the problems started, I only drive the dodge once or twice after the inspection.... Could this be the sensor that caused these problems?