I have a 99 F-150 4X4 Shortbed. I bought it new and had it shipped to England when I worked there for a few years. UK requires amber rear turn signals. I had a garage re-wire the brake lights to the backup lights and put amber bulbs in each. I am now trying to wire the lights to factory specs.
With a 2 filament single bulb (tail light and brake or turn signal) there is something else the garage rewired in order that the brake ckt does not over-ride the turn signal ckt. when the turn signal is activated. What was most likely done to make these ckts independent? Re-wiring the tail lights is pretty straight forward, but what else could have been done? Is there a relay or switch somewhere that could have been bypassed?

 

I have just wired mine so that the brake lights are independent from the turn signals.
I'm presuming you mean that the garage made the reverse lights into the turn signals with orange bulbs.
On the original wiring, there is a wire going from the brake light switch to the indicator (multi function) switch.
I had to cut that wire and feed it to the brakelights as a seperate wire.
The wire is light green in colour. You should be ablde to see if it has been cut under the dash.
This was the simplest way to convert mine to UK spec so hopefully, whoever did the wiring in the UK did the same.
Let me know how you get on as I may be able to help further.

 

Right on English Adam. Checked under the dash and immediately found the cut green wire and the new wire used to connect the brake lights. I'll work on it this weekend and let you know how things turn out. By the way, do you live up near Liverpool? I knew alot of Brits with American vehicles and they seem to be centered in the Manchester / Liverpool area. I myself have spent over 20 years (off and on) living in Harogate, NYorks.

 

Ok, if you have found the cut green wire, it should be simple to fix.
Just reconnect it where it was cut.
You will probably find that they have disconnected each stop/turn lamp and rewired that to each reverse lamp.
This has probably been done just under the bed where the towbar would go.
The reverse lamp wires are Black/pink so if any other colour is connected to them, change it back.

I live on the opposite coast of England. Gt Yarmouth in Norfolk.

 

No problems. Everything back to factory specs. I needed to do it because I bought a boat and trailer and the trailer plug was already wired to the original scheme. Just made things easier. Thanks again for your help. Been down your way a few times boating and scuba diving. Makes sense there are a few US vehicles in your area with Lakenheath and Mildenhall near by.

 

Glad to be of assistance.