Many car enthusiasts enhance their vehicle’s functionality with aftermarket OBDII gauges. These devices, especially Cheap Obdii Gauges, can offer real-time data and a customizable display, adding valuable insights without breaking the bank. However, a common issue arises: standby current draw even when the vehicle is off. For daily drivers, this might be negligible, but for cars used less frequently, like weekend vehicles, it can lead to battery drain.
This article provides a DIY solution to eliminate this standby draw, creating a cleaner install and preventing unnecessary battery depletion. The key is to modify the power source of your cheap OBDII gauge from a constant power supply to a switched one. In many older vehicles, like certain BMW models, the OBDII port’s pin 16 provides constant power, while pin 1 is a switched power source.
To achieve this, you’ll need to create a custom harness adapter. This involves sourcing a used OBD2 socket and a bare OBDII plug. By soldering wires from the used socket to the new plug, you create a splitter. The power wire for your cheap OBDII gauge is then connected to the switched power pin (pin 1 in some K-Line cars) instead of the constant power pin (pin 16). This ensures the gauge only draws power when the car is running.
The factory OBDII socket is detached from its mounting. Your new splitter harness is plugged into the factory socket, now behind the dash. The used socket from your harness is then placed back into the factory mount, effectively relocating the original OBDII port slightly. The cable for your cheap OBDII gauge, connected to the other branch of your custom harness, is then routed through, resulting in a discreet and efficient installation with zero standby current draw.
Remember, with this modification, only one device can communicate with the car at a time. For diagnostics or coding using the OBD2 port, simply unplug the gauge cable. This minor inconvenience is a small price to pay for eliminating battery drain and achieving a more streamlined setup for your cheap OBDII gauges.
