Hi Folks. I'm sure that somewhere in the dusty archives lies the answer to my delema, but I haven't been able to find it. So, in the hopes someone else has run in to this problem, I'm posting a new thread in hopes of a resolution.

My '73 F-350 Super Camper Special turn signals quit working after I removed an unneeded electric brake controller. It had been wired directly to the battery side of the starter solenoid for + and to the - battery post for ground. Before I took it off, the turn signals were working. I have verified all the light bulbs are good and the fuse is good since it also powers the wipers and washers and reverse lights. All are working. The emergency flashers are working. I've found there is voltage on the turn signal flasher itself and I cannot find any loose or missing grounds. I'm reluctantly getting ready to pull the steering wheel, but the visible portion of the turn signal switch that I can see through the gap in the steering column looks almost like new and there is no play in the switch itself. Plus, as I said earlier, it was working prior to removing the electric brake controller. I find it hard to believe that the turn signal switch died exactly when I took off the brake controller. It just seems a little too much of a coincidence. After removing the brake controller. Behind the dash, just to the right of the wiper switch, I found a black wire with an 2 into 1 open round "female" connector. We used to call these type connectors "banana" plugs. But I cannot find a corresponding "male" end anywhere that it might connect to. If anyone has had a similar problem, I'd really like some ideas where to look. All the fuses are good and the "always hot" and "switched" are working properly. Everything else on the truck works normally. Just the turn signals are not. I've also replaced the turn signal flasher with a new one. No help. Can anyone think of anything I've missed? Thanks in advance for any help.

 

Been there, done that, for lighting issues. They can be a riddle sometimes.

Is it both front and rear that won't work?

Was there anything from the brake controller spliced into the stock wiring? If so, check to make sure none of them have broken wires.

Check and clean all grounds.

• The two at the rear (behind the lenses)
• The two at the front (on or near radiator support) I think one is hidden/hard to get to by the battery tray.
• Grounds from batt to block and block to frame and firewall.
• Any trailer light wiring including its' ground.
• Check all light sockets with a multimeter or test light. Sometimes they can get rusty/loose on the inside etc...

 

And look for other custom trailer wiring along the driver side frame all the way to the back.
Not sure how it was done in 73, but in later years, there was a connector towards the rear that they might’ve spliced into.
Camper specials also sometimes got a funny looking Connector mounted to the frame rail adjacent to where the gap is between the bed and the cab. Look for one of those and make sure nothing has been spliced into it.

and yes, we run into “coincidental failures“ all the time here! It’s so frustrating when that happens!

 

Turns out the issue was an intermittent open connection in the hazard lights switch that prevented voltage to the turn signals side of the switch assembly. That's one I had never seen before. The little switch with six connections turned out to be the culprit. Found it with the help of a youtube video.

 

That’s great! And thanks for following up and letting us know.
That exact subject has come up two or three times in the last month as a matter of fact. The hazard switch causing issues with the turn signals.

and I guess it did turn out to be one of those “coincidental failures“ after all! Related, but not directly related to your work under the hood.