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Ford F-Series Electrical and Lighting Problems



  • If your positive you have wired it right, try the following.

    One or both of the lamps are cheap and have a short. Try conecting them temporarely right at the battery with shorter wire. Verify the lamps are good.

    Fog lamps are by design to go on the front, a shorter distance. Sometimes the guage of the wire isn't large enough to handle the extra length. Extra length means more amps going through the wire.

    Depending how many watts each lamp is, you may have to just wire them sepperately from their own relay, same switch. Relays typically can only handle 30amps, thats about 400watts. If each light is 200watts, with the extra length your way over the max. The formula for solving if you know your algebra is watts=amps time volts. Looking at the bottom of your relay , it should be wired like this;


    For Accessory

    | |
    I+ --> | | <---Ground

    | B+

    Good luck
  • idfordidford Posts: 1
    I have a 2002 F150 King Ranch crew cab. After I turn the ignition off the interior lights stay on. I have finally removed the Fuse relay that controls the interior lights. Is the fuse relay bad or is it something else. Any help would be appreciated. Thanks.
  • Ford used various designs and features for this, but this is what you can do. Please make sure that the dimmer switch is not turned all the way up turning the light on. Next, if the light just wont go off by itself after exit. try exiting through passenger side. If problem is still present, unlikely that its the door switch. By the way, you will have to put the relay back in for these test. If this is a common type relay try switching it with one of your other ones. Relays rarely go bad. Next, test the relay socket for the ground that comes from the door switch. Ford also used a positive on some models. If you have the time delay feature for when you open the door or lift the handle, there may be a problem with that.
  • I had the same problem with my 2008 f250 the interior light ould not go off. took it to dealer and they reflashed the computer . Had no problem since.
  • 2002 f250 superduty diesel

    I hooked up a trailer with a short in the trailer wiring and lost my head lights and tail lights. checked all fuses ok, took it in to a garage and they think its the whole fuse box / control module. any ideas on problem and fix ???
    thanks rv
  • Assuming that the diagnosis from this shop is right, you only have 3 opions;

    Get it fixed.

    Drive only during the day.

    Or hard wire the system so everything works from your switch. If you have the headlight delay feature, by passing the moduel will eliminate this feature. Good luck with it.
  • My best guess would be a fusable link, possible under the hood, but I can't say for certain. You may want to consult a Ford truck mechanic (not just some pinhead walking around the service dept). I looked on my 2004 diesel F-250 but it's near impossible to see with the mass of wiring under there. Good luck. KF
  • 2005 F-150: The brake and turn lamps on my taillamps are not illuminating. Not the fuse. I can't seem to get the lamp housings off to check the bulbs even though I removed the two screws on the side after opening the bed door? Thanks for suggestions.
  • They may be just stuck, new you know. The only other thing holding those in are some push in one way lock tabs. You may have to wiggle them a little, but pulling straight back is how they come out with those screws removed. It sounds like your breaking the thing when those metal spring locks start to release.
  • vibe98vibe98 Posts: 6
    what can be the cause of the tail lights and the license plate lights not to work. I have change light bulbs, the light switch and the fuse inside the truck under the dash. Any suggestions?
  • Do you have power and ground at the socket? With what you have already stated you must be missing one of them. If you have power going through the fuse, and I mean you tested it with a test light. It could be something wrong with the harness. I would double check the bulbs you used, and make sure they are pushed into the sockets correctly. The little metal tabs sometimes bend out of shape. Test the socket for power and then repost.
  • vibe98vibe98 Posts: 6
    Well it has been -4 degrees with an wind chill of -20 but I am doing my best to check the sockets.

    I do have brake lights, hazzard lights, change all light bulbs in the tail lights again, change the fuse in slot 18 with a 5amp fuse, plus I do have front parking lights and hazzards and headlights. But no tails and license plate lights. I did locate the conector for the wiring harnes also and i wiggle it hoping something will happen but to no avail.

    Seems no fuse are getting blown. Licenses plate bulbs look good too. I am still stump. Any suggest now besides checking the power and ground?
  • Your parking lights are on the same circut as your tail lights and license plate light. Forget about your other lights for now. You either are missing ground or positive for the tail lights and plate light. Take a test light to one of the sockets and see which one is missing. You may have just lost a good enough ground for the bed of the truck.
  • vibe98vibe98 Posts: 6
    The wire harness under the truck bed by the shock was cut. It probably happened when I changed out shocks by the shop. The wire loom was melted through plus the black tape was melted. Thanks for all the help.

    How much would a wire harness cost from the back to front?
  • How much would a wire harness cost from the back to front? You would have to check with the dealer on that. I'm willing to bet that after you do, you will decide to repair the one that is damaged.
  • vibe98vibe98 Posts: 6
    They told me about $1000 but did not tell for sure even though I did ask. But it was 6-8 wire that were cut and melted the wire loom plus the black tape. Just that alone costed me $377.12, $356 for labor and $20 for parts. They resolder the wires and put on a fresh loom and tape. Yeah I guess this is the cheaper way but I still wanted to know about the harnes.

    Be care whenever you chage shocks that no one melts your wires.
    P.S. any where I can get a diagram of the wire harness of the F150 series?
  • bladblad Posts: 1
    2003 f350 my wiper dont stop even if truk is off i need help
  • What would cause my 1998 ford f150 with 192,600 to blow 3radiators in one year.
    I have a new one now that was under warranty but it would be nice to figure why the right side seals are going bad.

    Any sugestion.
  • kowenkowen Posts: 1
    2003 f150. Noticed the left turn signal stopped working but only when my headlights are turned on. Then found that my brake lights go on with my headslights as well. Changed signal and high center brake bulbs and visual check all fuses - ok. Out of my mind with this problem.
  • I have a 05' f-150 with power door locks that dont work from the door switch, but work with the keyless entry and shift from park feature, my question is , is there a relay for the door swith and if yes where is it located? thanks...........
  • If the keyless entry will lock the doors your problem might be dirty contacts on the the door switch itself. If the passenger side switch will lock the doors I would concentrate on the door switch first.
  • Neither door lock switch works, this problem occured after installing an aftermarket remote starter, when I tried to operate the new remote door locks, I seen a spark from under the steering column. something must have blown and guessing a relay
  • I guess no one can help me..............great forum..........
  • KCRamKCRam Mt. Arlington NJPosts: 3,516
    Be patient... not everyone who reads the forums will have the answer, and those who do may not read the forums every day.

    kcram - Pickups Host
  • I doubt that it is a relay. Most likely your after market remote shorted something out. Recommend close examination of the area that you saw the sparks. Check fuses in interior fuse box and engine compartment. There is a third relay box usually mounted under the dash, drivers side near the heater defrost duct. It holds about 10 relays is black with a black cover. Your relay for power windows, power locks ect is in there. I think your wasting you time checking that first though. Shorts usually occur where the wires melt, sparks ect. My guess is that a power wire that is suppose to be hot at all times, shorted out with your new remote. Either your circuit protection blew a fuse, or a wire melted to ground. The power door lock circut is hot always with the key on or off.
  • dglarsondglarson Posts: 4
    I have a 1982 F150, Straight 6 with automatic transmission with the following problem. With engine running but sitting in park the wipers, turn signals, emergency flashers and heater fan do NOT work. I put the vehicle into Drive and the wipers start working but the turn signals, emergency flashers and heater fan still do NOT work. With the Engine OFF but the ignition key turned to On, the wipers, heater fan, emergency flashers and turn signals all Work.
    This is clearly some kind of electrical problem but I don't know where to look or start.
  • wpalkowskiwpalkowski Posts: 493
    From the weird behavior you describe, it sounds like maybe the clock spring inside the steering column may be on its last legs. It makes all the electrical connections for the compnenets inthe steering column.
  • mtap007mtap007 Posts: 5
    this is a manufacturer problem that they will not admit to. Nevertheless, the best way to corrent this problem is to undo the negative post to your battery for about 2 minutes. This will send a message to your computer to reset everything in your truck and the light will be off when you hook it back up. You will have to reset your clock but other than that it will work fine.
  • bpaulsonbpaulson Posts: 1
    I have a 1999 F-250 with a 7.3 powerstroke diesel. Couldn't get it started this morning, so I put a battery charger on it. Two hours later and nothing. Jumped it, turned over but wouldn't start. During this time the alarm went off intermittently. Batteries checked bad, so I now have two new batteries installed. When I turn the key, I hear the solenoid under the dash click, but nothing else. No cranking at all. All lights/chimes work great. Possibly related...when I lock it with the FOB, the horn beeps instead of the alarm chirping. I've turned the key on and off 3 times, pushed the black valet button with the key on (service guy's suggestion) but no luck. Any suggestions?

  • mtap007mtap007 Posts: 5
    This has been a problem for not only that model but the 1997-98. Try replacing the solenoid first. Also have the alternator checked and let me know it this corrects the problem.
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