Part One - Brake Light Mystery

[Rob-a-Billy]

I was moving over the weekend and since I can't tow my cargo trailer with MY truck, I had to borrow someone else's (see Part Two). While I was following the driver of MY truck (1969 F-250 C/S) I noticed a peculiar happening with the brake lights. I called the driver and we went out on a quiet stretch to test out the different ways of signaling and stopping - here is what I discovered:

No Signal + Brake Applied = Brake Light Right OK; Dark Left

Right Signal First, Then Brake Applied = Brake Light Left; Right Signal OK

Brake Applied First, Then Right Signal = Dark Left

No differences with Headlights on, or just tail-lights.


What would make the brake light on the left only function when the right signal is applied FIRST? I am stumped.

[kaptnkaos]

Hey Rob-a-Billy...

I just went through that with my 68' CS, it was the turn signal switch.
That's where the power from the brake light switch is routed so it goes to each side.
The turn signal over rides it when the brakes are on.

KaptnKA S

[Rob-a-Billy]

I replaced the turn signal switch with a new one.

[Thunderfoot]

Check the ground connections on the left rear and left front bulbs (socket to chasse ground connection)

[Chaseman]

Always remember to use Di-Electric Grease on all electric connections while you have them apart.

[Rob-a-Billy]

Check the ground connections on the left rear and left front bulbs (socket to chasse ground connection)

The rear light is screwed securely to the fender and the ground appears to be good - no rust, paint, undercoat, etc.
The front light ground wire is solidly screwed to the front fender, as well.

I was able to get the new cargo trailer's lights to work with your 4-flat installation instructions - God Bless You! I am very grateful. However, the trailer is experiencing the same phantom brake light as the truck. The left one just won't come on without the right signal on.

Any other ideas?

Oh, by the way, The harness between the Voltage Regulator and the Alternator absolutely FRIED today. Complete Meltdown - Any ideas for a harness source?????

[basketcase0302]

Rob,

Sorry about the melt-down, kinda sounded like your turn signal switch to me also.
As far as source for wiring harness...
You can pull a used one from a boneyard bump,
or:
http://www.painlessperformance.com/gallery.php
(Although I don't have any personal expierence with it)...
Several on here have used the "painless" harness and liked it.
I remember one occasion where the member couldn't get "squat" to work after using the same "new" harness.

Here's one more:
http://www.centechwire.com/catalog/fords/k40f.shtml

Jeff

[Chaseman]

I think Ron Francis has a harness for our trucks

[Rob-a-Billy]

It turns out that my "meltdown" was just the Black/Red Stripe wire from the Alternator to the ground at the VoltReg Base. It was connected to the Stator Terminal on the Alternator; NOT the Ground terminal on the Alternator.

I have the Alternator out and am attempting to repair the fried wire. I'm going to create a new post with the Alternator Connection Questions that developed in my mind...

Thanks guys...