Electrical issue with directonals and back-up lamps (68-RS)

[DonSTP]

   This is killing me!

I just developed an electrical issue with my directionals.  Here's the scenario:

- I've troubleshot with my voltmeter and and see power on the Pink wire to the directionals flasher
- I flip the directional switch on the steering column and see power applied up the column via the Purple wire
- NO DIRECTIONALS

The directionals worked just fine prior to me using the power-top convertible switch under the dash (I have a Convertible RS).  The switch wasn't responding so I worked it a little harder and the top went up, but then that's when the directionals stopped working. 

Unfortunately, I haven't seen any wiring diagrams which show how the power-top switch interacts with the rest of the harness.  Could it be that there's some interaction with the directional switch in the column?!?

Second issue:
I also have power to the back-up tail lights on my 68-RS, but no illumination.  The bulbs are brand new and correct part number (1156).

I don't believe my directionals problem has anything to do with the reverse lights not working.  I can certainly see how the Pink wire goes to the floor shifter, but I've troubleshot the floor shifter switch as well and very clearly see the power get applied to the Green wire, which goes to the reverse tail light bulbs.  I remove the tail light bulbs themselves and put the volt meter into the socket and I SEE POWER!  What is going on!

Help!

[tom]

Tail lights: I would look first to a grounding issue.

Directionals: Check the flasher, and the ground.

Both: make sure you have the right bulbs, and the wire is not shorting out someplace. Sometimes the worng bulb will fit, but not make the contact.

Electric can drive you nuts.

Tom

[DonSTP]

Ok got an update.

I pulled the steering wheel (easy part) and replaced the directionals switch in the column with a new one.  Replaced column and streering wheel, and...no directionals!

So back to square 1, except I'm $72 dollars in the hole for a new directional switch harness.  I guess it could be worse, I could have paid someone $45 dollars an hour to do what I did, which took nearly the full day.  Labor's not cheap, but then again nor is my time...

So - I believe I've got a nasty ground situation somewhere.  Problem is, I did a full frame-off resto about a couple years ago and replaced all the wiring with new.  Everything worked great, until...

I'm open to ideas. 

Thanks,
Don

[hotrod68]

This may sound dumb, but do you have a flasher in the turn signal plug? There are 2 separate flashers...one for the 4-ways, one for turn signals. The 4-way flasher is in the fuse box...the turn signal flasher is under the middle of the dash in a separate, loose-hanging plug. When I put the wiring back in my '68 after resto I forgot the turn signal flasher and didn't have any turn signals either--it's easy to overlook.
  Also, you can put the taillight/brake/turn 1157 bulbs in 180-degrees off, which screws up the polarity of the turn signal circuit on that socket--they'll light up, but won't blink. Good luck!

[DonSTP]

Thanks for the follow ups guys.

I have flashers in both sockets (fuse panel and pink / purple wire connection under dash).  I found a post on our forum here about swapping the flashers - I tried this and the directionals still didn't work.  I even bought a new flasher (cheap - $2.50) and no difference. 

So after extensive troubleshooting all day yesterday I believe I've got a bad ground somewhere.  I just have no idea where, and the schematics for these cars aren't that great. 

Anyone have any suggestions on troubleshooting for bad ground somewhere?  Starting around the wire harness under the dash?

I'm really bummed.  It's been gorgeous here and I can't drive b/c my inspection sticker is past due and I've got no directionals.  No directionals...no inspection sticker. 

Thanks -

[fireZ]

There is a philips screw that goes into the dash through the speedo cluster housing. It is between the speedo pod and the fuel pod at the top of the cluster. A screw has to be through this plastic cluster into a metal tang on the dash. I had problem with my 68 Z and after making sure the screw was in properly I had no dash or lighting issues.

[Blown 67 RS]

Your flasher is on the ground loop and needs resistance to operate correctly. Defintely sounds like a ground issue. And the dash wiring is where I would start.  It is possible that your turn signals were grounding through another access and you disturbed that by monkeying with the top switch. If you have a bad ground, the circuit will find its own ground or fail. Your body is the ground for most lighting bases, so I would even double check your frame to body ground strap in the search since you said you lost the reverse lights also.

Q: When you get power by using the meter, where are you grounding the negative lead? A volt meter will show power but the bulbs will draw more current and that is where the bad ground can/will fail.

Q: Do the indicators light bright when you manually flick the signal lever?

Q: Did you by chance use any crimped eyelets for a ground strap when you installed the new wiring?