I recently bought a 2013 C-max SEL and want to install LED bulbs for the low beams. I went with a kit that I have used before for our 2014 Chrysler T&C. When the lights are on in acc mode, they work fine. When you turn the car on, they are on for 1/2 a second, then they shut off. I believe this is due to the wattage / voltage being lower than expected for the LED bulbs versus regular incandescent bulbs.
Does anyone know of an off the shelf bright LED kit that connects directly to the battery AND connects to the stock wiring going to each headlight so that the interior controls still work normally? Or is there some other workaround that someone knows of? I am in IT, but I do not know electrical work very much. I would not be comfortable with too much jury-rigging.
Also, if anyone has put LED bulbs in for the fog lights, I would like to do those as well. Does anyone know if those suffer from the same issue as the low beam headlights? If you know of a kit that would work for this, I would love to know of it.
The low beam LEDs likely shut off because the BodyControlModule runs a monitor in RUN mode and not in ACC mode looking for electrical faults in the circuits. See note below: IIRC, someone found that adding a resistor in parallel to the LED allowed their LED headlamp bulbs to work. Search for the thread / post. Also, the BCM use pulse width modulation to control the brightness for DRL implementation. You should not have any issues with the fog or high beam LEDs as IIRC, there is no monitoring of the circuits - just relay contacts on the BCM that close and apply 12V battery voltage to these LEDs.
I would not recommend cutting into the existing wiring harness / modifying the connectors (jury-rigging). Splicing into existing wiring to bypass the headlamp switch and BCM could be problematic and would likely need reversed when selling the car. The dash headlamp switch via a LIN communicates the switch position to the BCM. The BCM controls the low, high and fog headlamps and checks for circuit faults. The wiring from the BCM to the headlamp assemblies are in a 42 and 20 pin connector when leaving the BCM. These two wiring harness split (likely many times) to pull the correct 4 wires for the left and 4 wires for the right headlamp assemblies which are connected to a 14 pin connector at the headlamp assembly.
NOTE: Due to varying wattage ratings and the resulting current draw differences of certain aftermarket halogen headlamp bulbs, the BCM may activate its short circuit protection strategy, resulting in the low beam output circuit becoming inoperative. Verify the bulbs meet Ford specifications. If the bulbs do not meet Ford specifications, install the correct bulbs. Run the self-test (required to clear certain DTCs and reset the BCM . Correct any unresolved DTCs. Clear all DTCs. Test the system for normal operation.
Edited by Plus 3 Golfer, 18 June 2018 - 05:35 PM.