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Hi,

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.

 

Thanks!

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Hi,

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.

 

Thanks!

 

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
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Hi, my 2013 does not use daytime running lights, so thankfully, we don't have to worry about that. As I had said, many HID zenon kits would connect to the car's headlight connector on one side so that the switch on the inside of the car works correctly, then the set has another connector that goes to the headlight on the other side and the whole set up connects to the battery. My guess is that this would negate the BCM. if such does not exist in LED, then creating a setup that satisfies the BCM would be necessary.

 

So, you are saying I should be able to LED fog lights without issue because they are not monitored by the BCM? Great and thanks!

IIRC?

DTC?

LIN?

 

Is there an off the shelf setup for what you are suggesting for the low beam headlights?

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The headlamp switch on the inside of the car connects to the BCM by a Local Interconnect Network which is a single wire.  The BCM then knows the position of  the switch via the data transmitted over the LIN.  If I Recall Correctly,  the poster that placed a resistor across the headlamp LED used a kit not compatible with the C-Max (exactly what you are doing) and found upon installation the "issue".  He solved the issue by placing an appropriate sized resistor across the LED to increase current draw such that the BCM would not trigger a Diagnostic Trouble Code and inoperative headlamp.   IIRC, that was several years ago and perhaps now there is a compatible LED kit for the C-Max.   

Edited by Plus 3 Golfer
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What does IIRC stand for?

 

I am thinking of using a HID kit for the low beam headlights and LEDs for the fog lights. The HID kit uses a relay, connects directly to the battery and is sold by Opt7. I have used this kit before on another car with a couple nuisances, but otherwise it had great white color and brightness.  It is on Amazon - 

OPT7 Bolt AC 55w Hi-Power H11 (H8, H9) HID Kit - Relay Bundle - All Bulb Sizes and Colors - 2 Yr Warranty [5000K Bright White Xenon Light]

 

I am hoping that this eliminates the BCM issues.

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If you assume that DRLs operate at 2/3 power, the DRL current = 55W * (2/3) / 13.2 V  = 2.8 A current draw per bulb.   A 12 Volt relay coil will likely have a fairly high resistance say 75 ohms or so.  Thus, the relay will only draw 1/5 amp or so.  This draw is probably less than one LED headlamp draws which triggers the DTC.  

Edited by Plus 3 Golfer
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Thanks so much for all the help!

My C-MAX does not have DRLs - I had my wife double check to make sure - so does that change any of what you have told me? Also, you had used an acronym, IIRC; what is that? The HID kit that I mentioned has capacitors in addition to the relay. I thought the capacitors would help the HID lamps be "accepted" by the vehicles' systems, correct?

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The DRL current calculation was to show a known current level (for comparison with LEDs, HIDs) where the BCM doesn't trigger a DTC.   You mentioned the relay kit and installation of the relay kit will affect the current draw from the BCM compared to Halogens.  Now having said that, I just found a post on the Energi site that "believes" the issue with LED headlamps triggering a DTC is because the LED electronics "interferes" with the BCM electronics / monitoring.  By placing a 50 ohm resistor across the LED input, the poster got the LEDs to work (I believe in DRL and full mode as he changed configuration with ForScan).  So, there's a good chance that the relay kit will work as advertised with the HIDs as there are no electronics in the relay.  You could also buy a few 50 ohm resistors and try.the resistors with your LED kit and forgo the HIDs (and let us know if it works).  :)  You'd probably want around a 5 Watt resistor as the power would be about 3+ Watts based on the BCM voltage at 90% (see below). 

 

It appears that the capacitors in the HID kit are used to "smooth out" the voltage and current flow for vehicles that use Pulse Width Modulation.  The C-Max uses two PWM settings 66% duty cycle for DRLs and 90% duty cycle for headlamp. Evidently, this PWM can cause flickering of HIDS without the capacitors.  The relay kit obviously bypasses this PWM by operating the HIDs from the 12V battery.  

 

Good Luck!

 

If I Recall Correctly = IIRC

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  • 3 weeks later...

All, I was finally able to get the Opt77 HID kit I had mentioned. Using the included relay, I was able to get the zenon bulbs working in run or accessory mode with no BCM issues since the current is coming directly from the battery. The lights turn on and stay on with the car. The only issue I had was getting the negative lead attached to the post for that on the car. I had to macgyver a way to attach it. Next, I am going to try to install the LED kit I had bought before as fog lights - the kit includes amber filters for a good fog light hue.

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  • 9 months later...

I've found an LED headlight bulb that works perfectly with a C-MAX and doesn't change the beam pattern and is completely plug and play.  It's from Diode Dynamics, the SL1 H11 LED bulb.  I've installed it with the optional anti-flicker modules since our cars low beams are pulsed.  The anti-flicker modules are attached in-line.  The led driver and anti-flicker module fit inside the headlight and can operate with the dust cap on.  I'm pretty happy with them.

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