Okay...this one is different. 2001 F150 Supercrew 4x2 and the High-mount 3rd brake light stops working.

Checked the bulb and fuses all fine. Cab lights (to light bed) work fine. Other brake lights are fine.

Take it to the dealer to have it checked and they find a switch attached to the 3rd Brake Light wire. I didn't install it and I bought the truck new from the dealer. They indicated it was after-market.

Anybody a clue what a switch added to the 3rd Brake Light might do? The switch is small about 1x1.5x.75 with three wires (red with female plug; orange -not connected; and black with a slice clip that cuts into the brake wire on one side). On the other side of the switch are three smaller wires blue, green and white that just loop out and back into the box. It says it is a Model 628 Made in China.

Any ideas on what this does or where it might have come from on a new truck if not the dealer????

 

may be someone tried to hook up a switch to turn off the brake lights so when backing a boat trailer in to the water they didn't have to unplug the harness they just picked the wrong wire to switch.

 

Good thought. I did have the dealer send the truck out and put a Class III receiver on it. It was already wired though for the 4-pin trailer plug (what I needed for my boat).

I was thinking it might be a blinker/strobe switch for the 3rd brake light, but never seen one thus the detailed description of what the dealer removed today.

 

Where was the switch mounted?

JMC

 

According to the dealer it was hooked into the 3rd brake light wiring behind the driver's side kickplate (where ever that is exactly). I am really curious what this thing is and if by them taking it out I will have other problems is all.

 

Just a guess.....Someone tried to wire a swirch into the cargo lamp and blew it. You may have noticed that you cannot turn only the cargo lamp on via switch, it operates with the courtesy lights. Many have tried, and few have succeeded, to apply switched power to their cargo lamp. My guess is that the former owner attempted to tap the cargo circuit to power the lamp, then after fooling with it for couple hours gave up and left you with the mess you have now.

 

Not a problem. The dealer removed the circuit component and gave it to me. Still don't know what it is/was or who put it on the truck, since I bought it new from the dealer they don't know either. But the truck was a transfer from another dealer so the answer may lie at the first dealer who received the truck.

Oh well, the 3rd brake light works fine with the component removed and I have no plans to put it back on anytime, so I am good to go now.

Thanks to everyone for their suggestions and input. Guess just chaulk this one up to the wierd unknown switch component showing up magically on a new truck.

Later....Ken