Date: 201906
Local time of day: 1801-2400
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Night
Aircraft: Regional Jet 900 (CRJ900)
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Climb
Airspace: Class B ZZZ
ATC / advisory: TRACON ZZZ
Aircraft component: Service/Access Door
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Flying
Reporter qualification: Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument
Human factors: Confusion; Workload; Troubleshooting; Distraction
Second reporter function: Captain; Pilot Not Flying
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Maintenance
Detector: Person Flight Attendant; Person Flight Crew
When detected: In-flight
Result: Flight Crew Overcame Equipment Problem; Flight Crew Returned To Departure Airport; General Maintenance Action
Contributing factors: Human Factors; Procedure; Aircraft
Primary problem: Ambiguous

Narrative: Our plane had its service door wiring damaged upon servicing in ZZZ. The wiring to the door had been repaired previously by the numerous splices we saw and lack of protective wiring sheathing. Maintenance deferred the wiring on our planes service door and disabled the ground valve and returned our plane to service. Maintenance told us all was complete for us to fly and that door unsafe indications were to be observed on our upcoming flight and that their visual confirmation of the doors being closed was the approved method of deferral. I heard my Captain get assurances from Maintenance that ALL of the exterior doors that were worked on by Maintenance were secured and acceptable for flight. We received a YOU are Green on ACARS. Our Captain asked and received visual confirmation from the ramp push crew confirming that ALL doors were closed and secured before our push. Our Captain made an additional specific request that the avionics bay door in the lower fuselage be checked after the initial all doors secured was received. Prior to our taking the runway before takeoff; our Captain had me request a delayed takeoff so he could call Maintenance on the phone and once again confirm that all of the indications we were receiving were correct and that a safe departure could be made. Once on our takeoff roll we had numerous Comp Mon indications and I was instructed to continue the takeoff. Once airborne; cockpit noise was abnormal as was the pressure in my ears; to the point that it was very hard to hear the radio and interphone. The Captain was also having trouble hearing ATC and in communicating with me as he proceeded to diagnose the issue while I flew. I took over controls of the radios and flew while the Captain referenced the QRH. The Captain instructed me to stop our climb which I did with ATC's approval. I established our altitude to that of ATC's instruction of 9;000 ft. ATC asked if we could make ZZZ1 at our altitude and gave us a heading while we worked out what we were going to do next. I informed ATC that we would be returning for a landing at ZZZ and they asked if we're would be landing overweight. The Captain ran the numbers through the ACARS and we were under Max Landing Weight. I informed ATC of that and they gave us vectors rather than a hold so we could prepare for landing. The Captain informed the flight attendants; Company and made reassuring calls to the passengers informing them of the cause of the sounds they were experiencing and that all was fine. We then informed ATC that we were ready to return; they asked what runway we would like; we asked for 18R and preformed a routine uneventful landing and taxi back to the gates. We agreed not to declare an emergency because there was no imminent danger to the passengers; crew or aircraft.I think all of this could have averted had headsets been available to both maintenance personnel and the ramp push crews. Using hand signals and gestures between the Captain and the ground personnel were in this instance inadequate. We had to rely on the visual inspection by Maintenance and ground personnel who were supposed to be confirming that the hatches that only they could see were secure; due to our electronic sensors being rendered inoperative by Maintenance. I believe had the proper repairs been performed to the wiring and not just numerous splicing to the same recurring issue none of this would have occurred.


Second narrative: [Report narrative contained no additional information.]


Synopsis: CRJ-900 flight crew reported experiencing a pressurization problem during the initial climb; due to an improperly secured external service door.