In the Ford Ranger and Mazda BT50

Injectronics says it is seeing vehicles being presented to repairers for no left-hand side low beam and/or inoperative high beams and in many instances, the globe is being replaced but the fault is remaining.
Injectronics reports its customers have come across this fault on Ford Ranger PX 3.2L P5AT (2011-on) and Mazda BT50 UP 3.2L P5AT (2011-on) vehicles, with common faults and fault codes as follows:
• Headlight inoperative
• High beam inoperative
• Unable to communicate with Body Control Module (BCM) using a scan tool
• No left-hand side low beam
• B1470 Headlamp input circuit failure
• B1471 Lamp Headlamp input circuit open
• B1472 Lamp Headlamp input circuit short to ground
• B1568 Lamp Headlamp high-beam circuit open
• B1570 Lamp Headlamp high-beam circuit short to ground
• B1795 Low Beam Headlamp circuit open
• B1797 Lamp Headlamp Low-Beam circuit short to ground
Injectronics says the Body Control Module (BCM) detects a fault when the resistance is outside its normal tolerances. This can be caused by an open circuit in the system, such as a faulty globe, broken wire (short to ground), when aftermarket LED OR HID globes are fitted, or when accessorises such as light bars have been fitted to the vehicle without the proper circuit protection being added to the system.
After a complete check of the vehicle’s wiring is completed and any faults (such as burnt or exposed wiring, broken or water damaged connector plugs/wiring) have been rectified and the correct globes have been fitted as per the manufacturers’ specifications, Injectronics says the technician is directed to complete a scan of the vehicle’s diagnostic system to confirm the fault has been rectified with an activation test of the lighting system with a suitable scan tool. If the vehicle still has no left-hand side headlight or high beam function, Injectronics says the fault can be in the BCM itself.

The solution
The BCM in the Ford Ranger/Mazda BT50 runs a solid-state circuit protection system which monitors the load and resistances of the vehicle’s electrical system. If an abnormality is detected, the BCM cuts any circuit outside of its tolerance.
When a fault is detected, it triggers a counter in the BCM that can only happen a limited amount of times before the BCM cuts out the left-hand side low beam and/or high beams permanently and in some cases, communication with the BCM is lost.
In the case where the BCM has been identified as the issue, Injectronics says the only option for the technician is to replace the BCM. This is normally a dealer only option, but Injectronics says it can now test and repair the customer’s own unit, saving valuable time and money for the end user.

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