turn signal wiring

[71_blue]

I'm having problems with my 71 lighting. Step on the brake pedal and the running and gauge cluster lights are dim. Use the turning indicator and the running/gauge lights flash too. Turn on the headlights and the turn indicators don't work. I'm thinking it's the turn signal switch in the column which I replaced recently. The colors of the wires from the switch do not match the harness. Has anyone had this problem or can tell me what the wires from the switch do?

Bob

 

[Oldtimer]

Grounds.
Remove and clean lugs and mounting surfaces of ground wire, from battery, fender and block. Also ground wire from voltage regulator, to alternator, to block.

 

[Torkman66]

Agree. Start by checking and cleaning all grounds. Did everything work prior to you changing the harness?

 

[DirtDonk]

X3
While it may very well be that your new turn signal switch has failed already, fix/repair/replace grounds first, as said.
Including the ones at each light at all four corners.

Start there.

Is your body harness original? Or could it have been replaced in the past?

It’s unfortunate that for for the last 30 years or more, replacement turn signal switches have gotten worse and worse at matching wire colors.
Your ‘71 should have been pretty straightforward.
Starting in 73 even Ford messed around with the wiring, but it’s usually the replacement switch that’s mismatched.
Do you have a list of what your wire colors are from the column side? The body side?
For a list of which colors do what, you can match yours to the wiring diagrams here on the forums.
Maybe somebody can post a link to some of them.
Oltimer’s already here, and he’s got a lot of the factory info. Not sure about’71 though.

Has anyone found an archive of Seabiscuit68’s old diagrams yet? Paging ToddZ!

 

[71_blue]

Problem solved

I decided to start disconnecting joints in the harness to isolate sections. I unplugged the rear light harness behind the driver tire and nothing happened. Then disconnected the same harness at the firewall. Everything worked again! Followed this harness down the frame under the driver’s seat area and found the harness had come loose and was laying on the exhaust pipe. All nice and melted. Spent a few minutes cutting and splicing to fix it. Reattached everything onto the top of the frame and we’re all good.

We are getting ready to move from California to Kanab Utah in the next month and I wanted make sure the Bronco was ready for the 12 hour drive.

Thanks for the replies above.

Bob

 

[DirtDonk]

Good sleuthing. Glad you found it quickly, since working on the column is such a pain under the dash!
Usually, when someone is having trouble with just the rear, we often talk about running along the rear harness to make sure it's not getting too hot from dual exhaust. But in your case it never even occurred to me.

Glad it's done. Now for the next problems!
Have fun, and good luck on the move.

Pauil

 

[Grey owl]

You definitely have have a ground problem.

 

[Torkman66]

That was a HOT ground problem!

 

[DirtDonk]

Well, if you think about it, a dead short (to ground) from melted insulator can be, in fact, a "ground problem" in a real way!

Paul