56 f100. Good morning. I am pretty much wiring my tail lights from scratch. When I select left or right turn signal both turn signals go off at the same time. I have disconnected the running lights and the brake lights and still have the problem. The tail lights are very well grounded. Anyone have any ideas? Thanks Matt

 

Need more info, is it a stock column, GM column, aftermarket add on turn signal switch ???

 

Sounds like a ground issue. Everything has to be grounded to the frame with clean connections.....cab, engine, etc.

 

Sounds to me like he has only 2 wires running to the tail lights. Like I said we need more information on what he has.

 

The column appears stock although can't guarantee it 56'.There are six wires from the column not including the horn which is inside the column. 1 wire for the brake. 1 wire for the flasher. Remaining 4 wires for blinkers. My tail lights have two wires coming from them. 1 lights bright and one lights less bright when they are powered up. I have not wired up the front blinkers yet 'cause they have their own problems. Initially wired both tail lights to their respective sides and finally ended up with just one wire connected to one side. Gave up and called you guys.

 

Below is a attachment to a link of the wiring diagram. You need 3 wires going to the rear. Feed to the signal switch will come from the brake light switch.

 

 

one word... diodes, put one one each positive wire going to the lights, such that current can only flow towards the light.

 

Thanks everyone for the information. My problem is still a problem but by using your suggestions I have come to the conclusion that the internals in the turn signals are jacked up. I bought an inexpensive (but not cheap) aftermarket turn signal/hazard combo. The bonus is that it reminds me of Grandpa's truck. Also bought a new light switch. Didn't start out to go custom but I'll make it work. I will be talking to you soon if I still have problems when the parts arrive. Matt