Hi - I need help - more than usual...

I have a '94 F150 XLT 4x4 standard cab long bed.

The truck has a caP with a brake light in the rear window.

I can't get the 3rd brake light in the cap to work properly. I have the caP light spliced into 2 of the 3 wires in the driver's taillight.
The caP light will work fine with parking lights on or off when I hit the brake.
No parking lights on - the caP light is off. Perfect.
Parking lights on - the caP light is off. Perfect.
Brakes applied with parking lights on or off - the caP light is on. Perfect.
The problem is that when I use my driver's turn signal ( that's the side the cap brake light is wired to ), the cap brake light blinks with the driver's side turn signals.
So it won't pass PA inspection ( due 3/31/10, of course ).
It passed inspection otherwise, but this issue is KILLIN me!!!

I've tried every combination of wires between the cap light and the driver's side taillight - and no luck.

Here's twist #1 - the light on the back of the caB ( not the caP ) has a white lens on either side, with a red lens in the middle. I assumed that the center ( red ) portion would come on when the brakes are applied. But when I hit the brakes the center ( red ) portion of the caB light does not light up. In fact, it doesn't light up no matter what I do. The outer (white) portions of the light up when I open a door or turn on the dome light by twisting the headlight switch, but the center ( red ) section of the caB light does not work at all.

So - can someone tell me if the red portion of the caB light is supposed to light when the brakes are applied? I'm guessing '94 might have been one of the first years with a light on the back of the caB? My caP is very tight against the caB ( like maybe 1 inch of clearance ), and there is no way for me to remove the caB light lens to check it out unless I remove the caP, and I really don't want to do that.

Twist #2 - I talked to a mechanic/friend, and he said that I need to find a splitter with a delay capacitor in it. It gets spliced into the taillight wiring and, supposedly, when I use my turn signal with the brakes applied, the capacitor has enough juice to keep the caP light lit while the turn signal blinks, resulting in a steady brake light. What happens when I use my driver's signal is on but my brakes are NOT applied....I have no idea. Anyway, I've been to several parts stores and nobody has a clue what it is I'm looking for. I don't have any truck accessory places in my neighborhood, but if I have to drive somewhere to find this hen's tooth, I certainly will.

Any and all help would be GREATLY appreciated.

Thanks folks!!

Ron

 

That fix your mechanic talked about is a half assed bandaid. What you need to do is run another circuit through the brake switch directly to the 3rd brake light so that it isn't affected by the turn signals, I'm going to install this on my truck but haven't got around to it yet, but it's supposed to be nice here tomorrow so maybe I can have a go at it and let you know what I come up with.

 

Thanks Paul - if you have any luck please let me know. As you can tell from my avatar photo, my toys are typically a little older and don't have many electrical goodies...

 

Yea just tap the light green wire right at the brake light switch and run it to your center light.

That source is before the flasher unit and before the multi function switch.

If your pickup truck was a bronco, it already have a red/light green wire coming off that point just for that reason.

 

Thanks danr1 - so where is the brake light switch - is it at the top of the brake pedal near the pivot point - like you'd see on a '66 Mustang or any Ford from that era? Everything I play with is 40+ years old - and this is my first F150 - so any additional info/directions you can give me would be great.

I'll try searching the site some...but for some reason my computer is absolutely CRAWLING tonight...

Thanks again!

 

anyone else have some pointers??

 

it should be a little thing attached to the brake pedal at where the shaft for the master cylinder and the pedal meet.

 

Damn you and your awesome car!

 

Is this a 12v source? This is waht I was going to try.. I already have a cable run from the fuse panel to the cap for a dome light and have an extra wire I could use for the 3rd brake light.

 

Yes its a 12v source, just connect your light to it right at the switch for the brake pedal. (location included for "PaxtonShelby")

 

Finally had some time to tinker with the truck today, and I spliced directly into the light green wire coming from the brake pedal switch and ran a wire thru the firewall and along the driver's side framerail to the back of the truck to the cap light. Thank goodness everything works. So now I can finally get my inspection sticker...

Thanks for your help guys!

 

Well guys, hate to tell you but in the factory harness at the back of the truck near the connectors for the 7 pin harness hookup there is a wire marked 'brake light' or 'third brake light' (don't remember which). It has a sealed end from the factory and this is the wire supplied by the factory for "extending" the third brake light if/when a cap is installed so the truck is still in compliance with the Fed's mandated third brake light. Tap it and run to cap. As for a dome light for the cap no full time hot just the ign on / accessory hot in the 7 pin connector. I used a 4 wire flat trailer connector, one from the harness 3rd brake light to the cap's third brake light, one fused to the battery, one to a good ground in the back and one blank sealed w/ shrink tube. If I have to pull the cap I just unplug the 4 wire flat connector & lift it off (with help). The cab light is supposed to work your brake light in it is probably burned out. I disconnected my cab lights when I installed the cap, removed lens & unplugged. Only problem I have ever noticed is if lights, 4-ways & brakes are on, ABS light lights up don't know why.