Dash 8-400
Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Confusion; Situational Awareness; Troubleshooting; Workload
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Maintenance
Flight Crew Overcame Equipment Problem
Aircraft; Human Factors
While boarding for Aircraft X  in ZZZ; a beverage was accidentally spilled onto the trim control panel. It was cleaned up immediately; however the aileron trim seemed to short out and go to full left wing down position. After maintenance was contacted; the mechanics came out and did a thorough cleaning and inspection of the affected area. They completed operational checks and deemed it airworthy. During the flight to ZZZ1; there were no issues noted. After takeoff; some right wing down aileron was applied without issue. On approach into ZZZ1; left wing down aileron was applied to bring the trim to the neutral position. This caused the trim to start to go towards the full left wing down position. Pressing the right wing down button halted this issue and the landing was completed without further issue. We noticed there was condensation in the rudder and aileron trim indicators at the time of the issue.  Use the utmost care and attention when consuming food or drink in the cockpit and always place lid on any beverage that is not being consumed; regardless of the brevity of the break in consumption.
An Air Carrier Captain reported they spilled a beverage into the trim control panel prior to departure which caused the trim indicators to malfunction while on final approach to their destination. Maintenance signed the aircraft off as airworthy prior to the departure.