Dim head lamps

Tiny
MMCMINN1
  • MEMBER
  • 2010 FORD F-150
  • 5.4L
  • V8
  • 4WD
  • AUTOMATIC
  • 75,000 MILES
Low beam head lamps, dull amber color. Bought bright white bulbs. High beam lights nice and bright but not low beam lights.
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Monday, September 30th, 2019 AT 11:00 AM

7 Replies

Tiny
SCGRANTURISMO
  • EXPERT
Hello,

This could be a problem with the Field-Effect Transistor which is located in the Smart Junction Box also known as the Generic Electronic Module. They control the amount of current that is allowed to go through to each headlight. In the diagrams down below I have included diagrams with the location and layout with callout of the Smart Junction Box on your vehicle. I have also included a wiring diagram of your headlight circuits for you as well for reference. Please go through these guides and get back to us with what you are able to find out.

Thanks,
Alex
2CarPros
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Monday, September 30th, 2019 AT 3:16 PM
Tiny
MMCMINN1
  • MEMBER
Replaced the smart junction box and still have the same problem, dim low beam head lamps and bright high beam lights. Low beam dull amber color, high beam bright white. Anymore ideas? Can't see driving with low beam on.
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Monday, October 14th, 2019 AT 6:07 PM
Tiny
SCGRANTURISMO
  • EXPERT
Hello again,

Check the electrical connector that goes to the Smart Junction Box. You can purchase electrical connector cleaner manufactured by CRC at any auto parts store. It is specially made not to hurt sensitive electrical components. Usually in an electrical component like this why the light is dim is there is unwanted resistance somewhere in the circuit. The resistance is not letting the amperage flow through to the light bulb and that is why it is dim. Get back to us with how everything turns out.

Thanks,
Alex
2CarPros
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Monday, October 14th, 2019 AT 9:14 PM
Tiny
MMCMINN1
  • MEMBER
Checked and cleaned the electrical connection but no help. Bought a set of led head lamps and converted to led, can see to drive but no difference between high and low beam. Back original problem dim low beam head lights but high beam are okay, so I checked the voltage I have 12.09 volts (roughly) on low, both sides. I have 12.45 on high, both sides( truck not running)but with lights on auto and lights not on, I have 8.09 volts on the driver side low beam, but not on passenger side. Bad head lamp switch or shorting to ground some where?
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Sunday, October 27th, 2019 AT 3:03 PM
Tiny
SCGRANTURISMO
  • EXPERT
Hello again,

There is unwanted resistance somewhere in the "AUTO" circuit on your headlamps. The best and preferred way to determine where "unwanted" resistance is in an electrical circuit is the voltage drop method. I have included a guide for how to perform voltage drop testing in an automotive electrical circuit. I would first check my headlamp switch first and the the wire going from pin 4 of the headlamp electrical connector[auto pin]. Repair as necessary and get back to us with what you find out.

Thanks,
Alex
2CarPros
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Tuesday, October 29th, 2019 AT 1:02 AM
Tiny
MMCMINN1
  • MEMBER
Okay, I've noticed that the map lights have a dim glow to them when off, I'm getting feed back to the map lights. That tells me that I have a ground problem. Do you have a diagram of the grounding locations for the lighting circuit? I searched around the web but didn't see one.
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Wednesday, October 30th, 2019 AT 6:01 PM
Tiny
SCGRANTURISMO
  • EXPERT
Hello again,

I think we need to go another way on this one. If the map lights have a dim glow when they are off I think you have got a short to power in that circuit. For archival purposes though, could you please re ask this question as a separate question. It will help others who have this problem in the future. We will get you the information and help you then.

Thanks,
Alex
2CarPros
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Thursday, October 31st, 2019 AT 12:48 AM

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