[65Stanger]

So I noticed that my brake lights don't come on consistently. Sometimes when my lights are on, my brake lights will work. So I hopped to the challenge and first decided how the brake lights are engaged. On the lever to the pedal, there's a switch that goes up and down. With the key on Accessory, if I push the switch up or down by hand the brake lights come on flawlessly. For some reason, the lever doesn't engage the switch. Why is this? I've been trying to figure it out for a couple of hours (it's dark out, so I'm just throwing around ideas in my head.) I have come to the basic conclusion that since they do come on SOMETIMES, that it must engage sometimes. I'm thinking of hitting the switch and thereabouts with some WD40 and try to loosen it up. Anything I should do in particular to get this whole deal working?

~65

[Kevin45]

You might try the WD, but I'd wait until it is light out. Look at the switch and see if it needs adjustment. There should be a nut to adjust the position of it. Worse case....toss it and get a new one.

[red65mustang]

replace the $10 switch, it's not adjustable or cleanable and not worth getting slammed in the rear from no brake lights!

probably have it at the local parts store

use the diagrams I sent you to find the 2 or 3 connectors in the brake lights wires...pull them apart and clean them with 600 or so sandpaper,

the tail light housing mount sheet metal nuts are the ground for the lamps..they get rusty...clean under them or replace with standard nuts

want brighter brake lights....buy a roll of aluminum foil tape and line the inside of the housing....

fair chance the power wire from the switch to the lamps is shot and corroded...compare the batt V to the reading at the lamp socket...more than 1V drop...put "replace tail light wires" on your to do list next time you tear the interior apart

[65Stanger]

Can do. Thanks guys.

[trees]

65,Stang, the brake light wiring on the old Stangs is a little quirkey. The wire from the normally cold side of your brake light switch goes to your turn signal switch and then travels down the left and right turn signal wires to the tail lights. A common problem is in the turn signal switch: not the brake light switch. We went through two repo switches before we finally got one that worked. One switch behaved much like yours and the other one had was intermittent on the drivers side. Running lights and turn signals always worked with the two bad turn signal switches. It took us a lot of metering and studying the wiring diagrams to finally isolate the problem in the turn signal switch. We ended up tearing an old broken switch apart to see just how the one wire input from the brake light switch traveled to the left and right wires in the Off, Left Turn and Right Turn positions in the switch. Now those Ford Electrical Engineers were on some sort of roll when they came up with that design!!!

Trees

[red65mustang]

trees...great post...dang CRS, I had forgotten that....not "quirky"....stupid and dangerous....about 5 different ways to lose brake lights
I sent 65stanger the complete wiring diagrams by email for his b-day (18! wow) so he will see it

65'....test this with just a jumper before you swap the switch ....

to make the brake lights independent of the worn out turn signal switch and worn out headlight switch and all the worn dash wire and connects to all....and help make brighter turn signals and brake lights.....

what you want is a parallel permanent "battery direct" jumper with a 10amp* fuse to the brake switch connect.....easiest way to do it is trim a flat spade wire connect so it fits good and tight on the before the fuse power side of the interior lights fuse....other jumper end is a 3M blade style inline splice connect to the existing turn signal wire at the brake switch
(not clear enough-email me I'll hand draw (LOL) a diagram)

*fair chance the brake lights will blow a 10amp fuse....it shouldn't if the tail lights mount ground and power wire to the lamps are in good shape= "move up" replace wires from the under dash connect all the way to the lamps on the "to do" list.....use a 15amp for now if it blows

[red65mustang]

65stanger, apology,
I didn't send you the exterior lights diagram which explains the "quirky" brakes lights wiring....(will do when I find it).... which goes thru the square connector into the column to the turn signals....clean those connections also

just did remember another "quirky" (dumb) factory wiring problem....the main power feed wire (#10 black/yellow stripe) and the wires from the alt to the voltage regulator go down thru the unibody front lower crossmember....
from the factory, the only protection was tape....99% chance the regulator wires are totally shot from cracked insulation....

if you want to keep the voltage reg on the D-side front (dumb*), tie a string on the end before you pull the old wires out, so you can use the string to feed the new wires back thru the cross member

*the only regulator wire that goes into to the car is the idiot light, you can move and mount the regulator next to the alt where it belongs.....run a new idiot light wire along the head lights harness and splice connect at the fire wall plug

test the main #10 feed wire from the solonoid to the firewall plug for voltage drop and/or disconnected for resistance, if it is ok, retape all and add/cover all with "ripple" split PVC wire wrap cause it is "loose" and rubbing in the cross memeber

DEFINITELY....a worth while project
ps. if the main power feed tests bad, post results for suggestions