Seems my brake lights went out!

Turn signals work
Running lights work
reverse lights work

Changed bulbs
brake light switch


About 2 weeks ago I changed the license plate lights. Truck sat a until other night. I wonder if I disturbed a connection?

 

If the turn signals work on a 1994, then it's a safe bet everythings good from the multi function switch (turn signal switch) to the lights.

Time to check the wiring from the turn signal switch to the brake light switch (the switch mounted under the dash that the brake pedal assembly pushes on), and from there back to the battery.

Do you have a copy of the 1994 Factory Service Manual for your truck? For wiring, there is nothing - NOTHING - that is as good. Well, you can get by with the AllDataDIY wiring, but you can buy the FSM for the price of one year at AllDataDIY.COM and then you have it the second year (check on Ebay for the manual).

I don't know it's the same for a 1995 (which I do have the PDF of); but for a 1995, you have a 50A fuse G in the Power Distribution block that has a 10ga Red/White wire, that splices to a 12ga Red/White, that goes to the internal fuse block position 7. Position 7 (a 10A fuse) then goes out a 18ga Pink/Dark Blue ( maybe Dark Brown; it's listed as DB ) that goes to position 5 on the brake light switch. You can check all this with a trouble light; if you have power into the brake light switch, that's all good. From position 2 on the brake light switch, if the pedal is depressed, you should have 12V coming out on a 18ga White/Tan wire that then goes into the turn signal switch. Again, if you're under the dash, a quick check of the brake light switch would be that it goes to 12V on that wire when you press on the pedal (with your shoulder if you're laying under the dash if you're like me.) So - 12V to the multi function switch, it's the MFS. No 12V there but 12V into the brake light switch, it's the brake light switch. No 12V into the brake light switch, check fuse 7 in the fuse block. No 12V on the input, check fuse G in the power distribution center.

Once you find out where the 12V isn't, it's easy to figure out what part to replace.

THAT said - from my seat here, without testing, if I were tossing parts at it, I'd order both the brake light switch and the multi function / turn signal switch from RockAuto, and do the brake light switch first (easier to get to).

Even better, find a voltage tester that has an actual light bulb (not a LED) in it to test it.

RwP

 

The connection was rotted, like in the pictures. Respliced, taped, liquid glue and a new fuse...all set!

 

The thing is, the turn signals are the same filaments as the brake lights.

So no, the turn signals WEREN'T working, were they?

(Not counting the lights inside; that's a whole different subject.)

RwP

 

2 filaments in the bulb.

 

Yep, two filaments.

One for parking/tail lights, one for turn and brake lights.

RwP

 

How does that work then? The fuse for the brake lights also blew due to the short. That fuse controls the stop lamp, rwal module and key buzzer. The fuse for the running lights, turn signals are another fuse.

 

Where is the location of corroded connector shown in the picture above? Also how did you repair it? Can u show a picture of the repair?

 

They're wired differently.

Have you ever looked at the wiring diagram?

Power from the battery goes through a fuse, to the ignition switch, to the flasher module, and then to the multi function / turn signal switch.

Power from the battery goes through a fuse, to the brake light switch, to the multi function / turn signal switch.

The MFS/turn signal switch determines which feed actually gets fed back to the brake/turn signal filament.

(That's a bit of a simplification; but that does pretty well describe it.)

RwP

 

Passenger side rear connection going to the tail lights...I cut the factory connections out, and spliced the wires individually. I did not take a picture.

Ralph, I do not know what to tell you, the turn signals were working, but the brake lights were not.

I found the wire diagram from the FAQ section.