why are my lights dimming

Asked by Feb 13, 2015 at 11:52 AM about the 2004 Ford F-150 XLT Ext. Cab 4WD

Question type: Maintenance & Repair

when im driving the lights an heater dim when I come to a stop or take my foot off the brake, replaced the alternator an battery an still does it

3 Answers

Try replacing the fuses, and check your connections as well to make sure they are tight

21,140

Dimming lights are an indication the proper voltage is not being applied to the circuit. Remove the fuse associated with the lights. Use a digital volt meter and check for 12 volts across the two terminals. You may have a loose or corroded ground. Check the ground from the battery to the block and make sure it is not corroded. Also check the alternator with the engine running. It should read slightly over 14 volts. Rebuilt alternators have been known to be bad out of the box.

2 of 2 people found this helpful.
72,505

Some fluctuations are normal. But if it's more than a slight fluctuation, check the belt. It may be worn and/or slipping. If this only occurs in wet weather look for a missing splash guard. The belt may be getting wet and slipping as well. HTH. -Jim

Your Answer

F-150

Looking for a Used F-150 in your area?

CarGurus has 224,485 nationwide F-150 listings starting at $1,200.

ZIP:

Ford F-150 Experts

  • #1
    OJ
    Reputation
    9,470
  • #2
    dandyoun
    Reputation
    4,650
  • #3
    tennisshoes
    Reputation
    3,270
View All

Related Models For Sale

Used Chevrolet Silverado 1500
2,746 Great Deals out of 175,328 listings starting at $955
Used GMC Sierra 1500
1,228 Great Deals out of 64,898 listings starting at $999
Used Ford F-250 Super Duty
449 Great Deals out of 49,398 listings starting at $1,899
Used Toyota Tundra
704 Great Deals out of 34,374 listings starting at $1,500
Used Dodge Ram 1500
411 Great Deals out of 11,096 listings starting at $1,500
Used Toyota Tacoma
722 Great Deals out of 45,870 listings starting at $2,500
Used Ford F-350 Super Duty
384 Great Deals out of 27,236 listings starting at $3,000
Used Ford Mustang
594 Great Deals out of 39,960 listings starting at $1,895
Used Chevrolet Silverado 2500HD
395 Great Deals out of 30,738 listings starting at $1,995
Used Nissan Titan
285 Great Deals out of 17,826 listings starting at $3,500
Used Chevrolet Tahoe
828 Great Deals out of 42,143 listings starting at $1,987
Used Chevrolet Colorado
344 Great Deals out of 38,619 listings starting at $1,595
Used Ford Explorer
1,263 Great Deals out of 70,145 listings starting at $1,000

Used Cars For Sale

2018 Ford F-150 For Sale
13 Great Deals out of 121,540 listings starting at $20,313
2017 Ford F-150 For Sale
198 Great Deals out of 27,293 listings starting at $17,298
2016 Ford F-150 For Sale
220 Great Deals out of 7,860 listings starting at $15,552
2015 Ford F-150 For Sale
525 Great Deals out of 11,426 listings starting at $11,990
2014 Ford F-150 For Sale
763 Great Deals out of 15,429 listings starting at $9,990

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.