Date: 202009
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Daylight
Aircraft: B737 Next Generation Undifferentiated
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Climb
Airspace: Class B ZZZ
Aircraft component: Horizontal Stabilizer Trim
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Second reporter function: Captain; Pilot Not Flying
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Weight And Balance
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Air Traffic Control Provided Assistance; Flight Crew Landed As Precaution; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Returned To Departure Airport; General Flight Cancelled / Delayed; General Maintenance Action
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: I was flying as the FO (First Officer) off[Runway] XXR in ZZZ. After liftoff I attempted to trim the nose up and there was no response from the electric trim. I notified the Captain and we continued the departure and cleaned the aircraft up. I reverted to the manual trim wheel to adjust the trim. Due to the load on the airplane; the wheel was moderately difficult to turn. I was aware that I could unload the aircraft to make it easier but I did not feel the need to upset the passengers at that time. The Captain tried his electric trim which also would not trim the nose up. However; the electric trim would trim nose down. We then leveled off at 11;000 ft.; [requested priority handling] and ran the trim inop checklist. As the flying pilot; I only flew the airplane and talked to ATC while the Captain managed the [situation]. The checklist directed us to disconnect the trim system and fly a flaps 15 landing. We chose [priority] return at ZZZ and landed about 7;000 pounds overweight. We also called a deadheading check airman up to the cockpit as an extra set of eyes. I configured early so that I wouldn't need to trim much on final. The overweight flaps 15 landing was uneventful. ATC was very accommodating. I know I checked the trim system on the ground and it tested good. The Captain had a habit of resting his knee against the trim wheel I and recall warning him to move it prior to the check. At the gate maintenance boarded and we showed them how it would trim nose down but not up. Upon further inspection we realized if we trimmed all the way nose down it would then trim nose up; but only for .5 seconds before stopping again.


Second narrative: During climb out with my FO (First Officer) at the controls; he proceeded to trim the aircraft up with no response. I tried it on my side same no response. The aircraft would trim down but not up. We continued with our departure and climbed to 11;000 ft. FO is flying the aircraft manually increasing the airspeed to 230 Knots. Heavy weight aircraft. Engaged the AP to see if we could get the aircraft to trim. Same non response with the Stabilizer out of trim light and the speed trim light coming on at the same time. Both went out when we disengaged the AP. [Requested priority handling]. Ran the QRH for the Electric Trim Stabilizer Trim Inoperative. Consulted with maintenance and contacted Maintenance Control via the ACARS. Aircraft was hard to trim manually but it did work. Proceeded back to ZZZ and landed without incident.


Synopsis: B737 flight crew reported electric trim malfunction during climb.