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84 F150 Brake light issues

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Crixmix

84 F150 Brake light issues

So hoping someone might have some info for an issue I’m having. My brake lights randomly stopped working. Naturally I switched out the bulbs and fuses and still no luck. Also my left turn signal is working but not my right and the bulb is the same for brake and signal but I attribute the right signal not working to a broken turn signal cam. So then I replaced the brake switch and still nothing. I realize this is now probably a wiring thing but I have no clue how to find the issue as I’m electrical is not really my strong suit. Any help or info would be greatly appreciated

Chris R
Loretta is my 84 F150 302 2wd AOD

ArdWrknTrk

Re: 84 F150 Brake light issues

Administrator

Chris, have you changed the turn signal switch in the column?
Are you sure that all the pins and the ground wire there have a good connection?

There are variants of the brake light wiring, and I'm going to ask if you have Speed (cruise) Control in your truck.

There was a recent thread about a very similar problem, with some very good diagnostics.
Let me see if I can find it.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

Crixmix

Re: 84 F150 Brake light issues

Hello
Yes I’ve replaced the switch once before and it seems it has broken again. The left turn signal stays in place and works but I have to hold the handle up to activate the right turn signal. Both indicators on dash flash but only the left signal turns on.

Yes I do have cruise control but it doesn’t work at all

Chris R
Loretta is my 84 F150 302 2wd AOD

myrl883

Re: 84 F150 Brake light issues

If you look at the wiring diagram, power feeds the brake light switch, then goes to the turn signal switch to be split left and right. The turn signal switch controls the brake light whether the turn signals are on or off. So, a turn signal switch can cause all sorts of problems with the brake lights.

Ford Parts Monkey since 1985
1981 F100 Flareside - Black, 302-4V Roller/AOD
1986 F150 Flareside - Medium Fire Red 302/AOD
1989 F150 Standard Cab 4x4 - Dk Shadow Blue 302/AOD
1993 F350 4x4 Crew Cab - 7.3 IDI/ZF-5
I think it's a sickness...

kramttocs

Re: 84 F150 Brake light issues

Administrator

In reply to this post by Crixmix

Do you have a multimeter? That will come in handy. For something like this you won't need a fancy one - voltage and continuity. A light up circuit tester will work for some tests also if you have one of those.

If you pull the hazard switch, any different behavior?

Scott
'Camano' 1986 F250 Supercab XLT Lariat 460/C6
'Chanute' 1980 F350 C&C 400/NP 435 - Gin Pole

But there ain't nothin' wrong with the radio

Crixmix

Re: 84 F150 Brake light issues

So I replaced the turn signal switch
Both turn signals now work. But still now brake lights. And yes I do have a multi meter just don’t know what and where to look for issues. Also when I pull the hazards switch my front hazards come on but not my back

Chris R
Loretta is my 84 F150 302 2wd AOD

kramttocs

Re: 84 F150 Brake light issues

Administrator

So:

1. All 4 turns signals work
2. Hazards only work in the front
3. Brake lights don't work

Seems odd that the hazard isn't working in the rear but the rear turn signals are. Trying to make sense of that.

For a simple test to rule it out, first check for voltage on the stop lamp switch. One terminal (Light Green) should get voltage when you press on the pedal. The other, LG/R (Light Green with Red hash marks), should have constant 12v.

For reference, here is the circuit from the 85 evtm

Scott
'Camano' 1986 F250 Supercab XLT Lariat 460/C6
'Chanute' 1980 F350 C&C 400/NP 435 - Gin Pole

But there ain't nothin' wrong with the radio

ArdWrknTrk

Re: 84 F150 Brake light issues

Administrator

Do the hazards and brakes work on the feed side of the circuit and the turns work on the ground?

I'm not that familiar with that schematic but you were deep in it last week Jonathan.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

kramttocs

Re: 84 F150 Brake light issues

Administrator

If the hazard switch hadn't just been replaced I'd put my money on it. The brake lights not working is one thing but I just can't come up with how the rear turn signals work but the rear hazards don't aside from a defective hazard switch.
If it was in front of me, I'd start probing the steering column connectors and tracking where the voltage is and isn't.

Scott
'Camano' 1986 F250 Supercab XLT Lariat 460/C6
'Chanute' 1980 F350 C&C 400/NP 435 - Gin Pole

But there ain't nothin' wrong with the radio

ArdWrknTrk

Re: 84 F150 Brake light issues

Administrator

The only thing I see common to Hazards & Stop rear, and not the turn signals is the 511 wire associated with the speed control on the right of the diagram.

Let me have a deeper look at this schematic, and see if I can be the electron..

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

kramttocs

Re: 84 F150 Brake light issues

Administrator

Good point Jim.

Could remove the connectors from the speed control module and see if that has any impact on the light behavior.

Scott
'Camano' 1986 F250 Supercab XLT Lariat 460/C6
'Chanute' 1980 F350 C&C 400/NP 435 - Gin Pole

But there ain't nothin' wrong with the radio

ArdWrknTrk

Re: 84 F150 Brake light issues

Administrator

This post was updated on .

If the T (between 'turn left' and 'turn right') is affected I think it has to be at the far right contact (below and after the d in hazard)

Or it is between that contact and the T itself.

It is that point where all these symptoms converge.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

ArdWrknTrk

Re: 84 F150 Brake light issues

Administrator

Not so much 511 going off to the speed control.
If that were shorted, he would keep blowing #1 (15A) fuses.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

Crixmix

Re: 84 F150 Brake light issues

Ok long time no respond. So i replaced the entire turn signal switch inside the column. My hazzards and brake lights worked. Then my brake light fuse kept blowing.It looks like the wheel was rubbing against a wire in the turn signal switch soooo i replaced it again. Now brake light fuse doesnt blow and everything works except!!! now my hazzards just stay solid on and dont flash? any idea how to fix this?

Chris R
Loretta is my 84 F150 302 2wd AOD

Gary Lewis

Re: 84 F150 Brake light issues

Administrator

Did you happen to put LEDs in? If so, they don't pull enough current to cause a regular flasher to blink.

Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

Crixmix

Re: 84 F150 Brake light issues

Nope
No LED they flashed prior to second replacement of turn signal switch?

Chris R
Loretta is my 84 F150 302 2wd AOD

Gary Lewis

Re: 84 F150 Brake light issues

Administrator

I'm lost. The circuit and bulbs are obviously good since the brake lights work. The only way I can see it not working is that you have a bad switch or a bad hazard flasher. But since you didn't touch the hazard flasher it isn't likely that. So that points to the switch being bad.

Gary, AKA "Gary fellow": Profile

Crixmix

Re: 84 F150 Brake light issues

oh boy.
maybe third time will be a charm haha.

Chris R
Loretta is my 84 F150 302 2wd AOD

Gary Lewis

Re: 84 F150 Brake light issues

Administrator

Did you keep the switch that had the bad wire? Can you put it back but protect the wire? Just for testing?

Gary, AKA "Gary fellow": Profile

FuzzFace2

Re: 84 F150 Brake light issues

Gary Lewis wrote

Did you keep the switch that had the bad wire? Can you put it back but protect the wire? Just for testing?

Little late but a flasher is cheap & easy to replace so would give that a try first.
If doing the switch just for testing he could just unplug the new from the harness and plug in the old for testing no?
This way he would not need to remove the wheel and sneak the wires up & down the column.

Also to get the wires up & down do they need to be removed from the hard plug then put back in the hard plug?
If so could you got 2 wires in the wrong slots?
Dave ----

Dave G.
81 F100 flare side 300 six / AA OD / NP435 / 2.75 gear
http://cars.grantskingdom1.com/index.php/1980-Ford-F100?page=1
81 F100 style side 300 six/SROD parts truck -RIP
http://cars.grantskingdom1.com/index.php/1981-Ford-F100