i have a 05 f150 my brake lights a are staying on but thats only when i have my headlights on when headlight are off lights brake and turn are working fine but also when headlights are on the right turn signal would stay solid but just changed flasher so now it just flashes fast and ive also changed both front and rear turn tail lamps still same issue sooo any one can help please

 

Why did you change the flasher ?

Did you do any modifications to the stop / turn tail bulbs ( i.e. LEDs ) ?

Are the headlamps factory bulbs ( vs. HID kit ).

Any other modifications that deal with the parking lamps / headlamps ?

 

no i havnt made any kind of mods i am a fire fighter and have added strobes to from and rear lights but none of the wireing or components are interfering with another and i eve have a sepperate fuse panel for the equipment

 

I am having similar problems with an 01 Expedition. The 5 amp fuse went out so I replaced it, then it kept blowing out. I replaced the brake light switch last night, but it blew another fuse. So now I am just pulling out the fuse when I get to where I am going, but before I turn it off. It seems the fuse blows when I turn the truck off. Any one had any consistent problems with this?

 

Identify the 5A fuse by fuse number. There are about 9 or 10 of them in that fuse box.

 

Sorry about that. I dont remember the fuse number, I will check it during lunch, but it was in the 4th row I believe. It is the one that controls the power windows, dome light and what ever stops the shifter from getting out of park.

 

Firefox, did you ever resolve this issue? I am experiencing a similar problem. Very vexing. I know it's not the MFS since I replaced it. I think I may end up chasing a fault. Thanks for the reply.

 

How is it different ? You posted similar, but offer no insight into the symptoms you are seeing.

 

This is info only. Vehicle: 1999 F-150 Supercab V6

I too had an isolated brake light failure. No other symptoms. Following some advise here in these forums, I disconnected the 5 wire brake light connector from the brake switch which is attached to the brake lever.

With ignition off I jumpered (shorted) the two green wires of the brake light connector with a straightened paper clip bent into a long vee shape. I then turned the ignition switch to "ON" and had my assistant verify that the brake lights were illuminated. This was a strong and ultimately accurate indication that the brake switch had failed.

With ignition switch OFF I replaced the brake light switch and the problem was fixed.

Tools:
Needle nose pliers, flashlight, hand mirror, knee pad, (black tape)

My Procedure:
- With flashlight and hand mirror inspect and memorize switch assembly. A single fancy cotter pin holds the whole thing together.
- With needle nose pliers remove the cotter pin while holding the assembly together with one hand.
- Slowly remove the assembly from the brake lever and the round brake actuator. ! Make note of the location and orientation of the plastic bushing ! (I didn't and had to figure it out at re-assemble.)
- The switch (very lightweight) is now dangling from the 5 wire harness. Disconeect carefully using thumb to depress the locking catch. It will be sticky.
- (tape up, or better still, replace cracked or split wires in harness.)
- Substitute in new switch, except cotter pin.
- Test.
- Install cotter pin.

Notes:
- Ford Part No. of failed switch: F87B-13480-A B (Mfg: POLLAK)
- Replacement Switch: Wells F4863 Cost: $14 inc tax 2May2011
- I am big. It was very awkward for me to do this job. I knelt with knees on pad on driveway, then scrunched in.
- Again - pay attention to the orientation and order in which parts go together. It's not overly complicated but a bit puzzling if you must do it cold...as I did.
- Total replacement time for me was less than 1/2 hour.

Comments welcome.

Keywords for search engines: 1999 Ford F-150 "Brake Light Switch" "F87B-13480-A B" F87B13480AB "Wells F4863"

 

I have a 1998 F-150 that is having the same problem. Rear turn signals work. Rear lights work when headlamps are on, but nothing for when the brakes are applied. All bulbs are good and I just replaced the brake switch. But still nothing is working after this. Not even the third brake light. Any suggestions to take this further?

Thanks

 

Did you mean the turn signals work with or without the parking lamps on ?

What my take away is, that the bulb, bulb connector and ground appear to be fine ( turn signals work with or without the brakes on ).

Q1. Does the CHMSL ( Center High Mount Stop Lamp ) work when the brakes are applied ?

If not, the issue seems to be from the brake switch to the splice where the brake switch out splits to the MFS and to the CHMSL.


This would explain why the stop lamps do not work, but the turn signals do, as the MFS at rest switches the output of the brake lamp switch to the rear Stop / Turn element on the bulb.


The diagram between those 2

 

No, The center mount third brake light does not work also. I am trying to grasp that diagram and follow it. I went out and messed the the brake switch again to see if i did something wrong and checked the connectors. Everything looks good and in place but still does not work.

 

Sorry about that.

the info on the CHMSL made me think, did you check the fuse for them ?

Quick test for the fuse & the brake switch is to use a meter or test light, ground 1 side, and the other put on the light green wire on the connector.

You should have + VDC when you press on the brake pedal.

I would suspect this to be OK, else you would not be able to get the truck out of park ( 97-03 had 1 circuit for the stop lamps and the shift interlock ).
You can get the truck out of park while running, right ?

If this is the case, the light green wire after the brake switch is the next test point.

 

One thing that I noticed was that my dual elements were switched around. I know it sounds odd, but the rear brake and and rear turn elements were somehow crossed. There is a "short" and a "tall" element. I forget off the top of my head which element is for which, but it is something to look into. I solved my problem by cutting the ground wire which runs from the rear off the truck up into the cab and grounding it to the top of the rear frame stay where the trailer ground wire connects. Not ideal, but it beats chasing a short and replacing wiring harness.

 

I have a 2007 f 150 and the Brake lights will work when they want too. Sometimes they come on and stay on some times they don't come on at all, sometimes they will come on and then go off. Any Ideas?