Yet another turn signal issue, both work at same time

[tommyjack 15]

Yep, that's right they work but both at same time.  No matter if it's left or right, they both light up and flash at the same time as if the emergency flasher were on.  They, emergency flashers, work fine by the way.  Any ideas were to start?

 

Thanks,

 

TJ

[Footcutter11 23]

Steering column.  That is where the circuitry is.

[tommyjack 15]

Spent a little more time looking at this afternoon. It's only the front signals that are flashing in unison. Rear signals flash as normal left or right but both front signals flash no matter which side is triggered and it lights up the scoop lights and dash lights as if the emergency flashers are on.

Replaced the original long flasher canister with a new one. No change. Unhooked parking light terminals at the front harness. All looked ok but ran same some sand paper across them and inside the female terminals. No change.  Turn signal harness?

[michael2938 24]

Replaced the original long flasher canister with a new one. No change.

 

Which one did you change?  The one on the passenger or drivers side?

 

-Mike

[69RavenConv 286]

The turn signal switch in the steering column is notorious for going bad on these cars. I'm on my 3rd one -- my original lasted 44 years, my first Scott Drake repop lasted 1 year, now I'm on my second. If you don't find a short between the 2 front lamps (unlikely IMHO), I'd suspect the switch.

[Regta 10]

I'm on my 3rd SD switch and it's now acting up.....These switches control everything

[tommyjack 15]

Changed out the passenger side flasher.  Also I'm buying a USA made switch, http://www.ebay.com/itm/281322955739?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT  Bought one from these folks two years ago for another 69 I had.  Didn't fix the problem so I figured it was a bad switch.  They were absolutely great to work with on the return.  After another switch and 2 weeks time, I discovered it was where I painted the tail light housings.  Bad ground, event though I thought I had cleaned them enough.  So they'll get my business again. 

[69RavenConv 286]

Thanks for the link. I wish I had known about Shee-Mar when my Scott Drake POS failed, I would have never dropped good money on a second one. I didn't know I had a choice, now I do.

[tommyjack 15]

Well. Switch came today so I changed it out. Still having the same problem.  So now I'm thinking printed circuit board???

[69RavenConv 286]

It's odd that the rears work ok but the fronts don't. Most general failures (like the PCB) would cause both front and rear to malfunction the same way. Is it possible the front harness got pinched somewhere, shorting the two lights together? Can you disconnect the front light harness at the firewall or radiator support and buzz for a short between the two front light sockets?

[tommyjack 15]

Don't have anything to "buzz" with.  I know it's not the hood scoop lights.  I unhooked them and it still does it.

[lanky 44]

How long ago did turn signals work properly? Recent wiring anywhere? Sounds like some wires are crossed/shorted somewhere. If the turn signal switch is operaing/installed correctly it can be ruled out, especially if replacing it did nothing.

[michael2938 24]

It shouldn't matter I don't think, but you could try changing out the drivers side flasher cannister?

[tommyjack 15]

No wiring issues before this.  Will check for short tomorrow.

[69RavenConv 286]

Don't have anything to "buzz" with.  I know it's not the hood scoop lights.  I unhooked them and it still does it.

 

Might want to invest in an inexpensive multimeter to chase this one down. Dumb question: do you have the right bulbs installed? I think they're dual element 1157A's for the turn signals. A single filament bulb in a dual element socket can short the lines together. The blinker signal could be back feeding the parking light circuit.

[danno 128]

There is a slim chance it is the instrument panel. Disconnect the connector on the back of the instrument panel, behind the temp and fuel gauge.  See if the problem remains with it disconnected.  Is this a 69 or 70?  The 70 has front side lights, I am not sure if they have connections to the flashers.

 

Otherwise, it almost must be a short between the wires.  I am also wondering if something by the switch could be making contact in it.  With the steering wheel off, loosen the bolts that hold the switch in place, and pull it away from the mounts about a half inch.  Then try the turn signals, see if something in the mounting is causing the short.

[danno 128]

It is possible you do not have dual filament bulbs in the front, that would also do what you are saying happens.  Do you know how to check if they are dual or single?   A dual has 2 filaments inside, and 2 contacts on the bottom.  If you have single filament bulbs, the turn signals are shorted to the parking lights, and that will turn on both every time. 

[danno 128]

I thought about this some more, and I know what your problem is.  It has happened to others on this forum.  You either have the wrong bulbs (mentioned above, but unlikely)  or you do not have a ground connection on the bulb sockets.   I will bet you a beer that if you take the bulbs on the front lights out of the sockets, then try the turn signals, you will see them work correctly on the hood scoop and dash panel.  This is easy to try, and I will bet I am right.

 

The problem is the shell of the light bulb is supposed to be connected to ground, which is the chassis of the frame. The connections get rusty or broken, and the connection to ground is lost. Electricity can go through your parking lights, and from them find a path to ground.

 

Give it a try.  Remove both front bulbs, and you will see the turn signals work correctly on the lights that remain.