A B1983 trouble means that your 2012 Mitsubishi Eclipse spyder's Engine Control Unit (ECU) has registered a short circuit issue in the unlock relay circuit for the driver's door.
The unlock relay circuit is in charge of receiving and relaying electrical unlock commands from devices such as a remote fob. In the event of a B1983 code, this circuit has suffered a short, and your 2012 Mitsubishi Eclipse spyder's convenient "power lock" feature won't likely function as a result.
Poorly wired and faulty wiring are common causes for a B1983 trouble code. Damaged or loose wiring can sometimes be explained by a recent crash impact. In a handful of B1983 cases, the ECU itself may be faulty, and reporting the trouble code falsely as a result. Although this shouldn't be realistically considered until the circuit-related potential causes have been ruled out, it may be looked into if you can't find anything wrong with the unlock circuit.
If the driver's door unlock relay circuit has been shorted out, it's very likely that the unlock feature of the driver's door will malfunction. At the least, the lock feature will operate unreliably. The B1983 will come alongside a stored trouble code and illuminated check engine lamp on the dashboard. These symptoms should be considered in a purely diagnostic context, and should be disregarded once the specific code problem has been identified.
Diagnosing the B1983 trouble code usually begins with a mechanic scanning the ECU with an OBD-II code reader. All electrical wiring relating to the unlocking circuit (including connectors) should be inspected and scanned for the source of the circuit short. Improperly wired, damaged, disconnected and otherwise faulty wiring should be sought out and noted when found. Potentially blown fuses, circuit-related components and the battery charging the system should all be looked over for signs of damage and fault. In addition, components that may have otherwise been fine may have suffered damage for the circuit short.
Body-related (or B-class) trouble codes may define different issues depending on the make and model of 2012 Mitsubishi Eclipse spyder. Inexperienced mechanics can misinterpret the code's meaning. If code descriptions are mistaken, this will result in unnecessary repairs and expense, all the while doing nothing to solve the real issue.
An unreliable unlocking mechanism won't have any effect on the technical drivability of your 2012 Mitsubishi Eclipse spyder. However, not being able to open or properly unlock the driver's seat door can pose issues of convenience. Luckily, physical workarounds (such as a physical key) can be used in lieu of the fob or electrical controls. As such, the B1983 trouble code should not be considered an urgent concern, although some 2012 Mitsubishi Eclipse spyder users will find the inconvenience enough to make repairs swiftly.
If any components (including the system's charging battery) have been identified as damaged, faulty or broken, they'll need to be replaced or repaired according to the severity of the issue. Any wiring that's been found to be damaged, disconnected or otherwise problematic should be addressed as needed. If the ECU has been found out as faulty, it will require replacement or reprogramming. Once you've made repairs to address the B1983 locking problem, restart your 2012 Mitsubishi Eclipse spyder and test the lock. Doing so immediately will let you know whether or not the issue has been properly addressed.
The process of repairing a locking mechanism will vary based on the type of lock system your 2012 Mitsubishi Eclipse spyder is equipped with. Single wire systems are generally the easiest to repair, although more modern 2012 Mitsubishi Eclipse spyders are typically equipped with tripe wire or even vacuum-engaged locking systems.