Beautiful - that's the kind of instruction I need since I'm not your typical FYI Ford expert. Thank you!!

Rick if you haven't forund anyting yet you can  check the other side of the plugs where the wires leave the steering column and got out to the lights. First you will need to remove all four turn bulbs. You will get a false reading throught the bulbs. Good time to check sockets for bent terminal and bulb placement as MS said.Make sure they are all correct bulbs. Pull the flasher and don't push the brake during testing. Once again measure ohms from each pin to ground. Should be infinite.If you want to jumper positive to see if each light works replace bulbs. The best thing to do is make a jumper with a fuse in the middle about 20 amp. That way if you short something out you blow the fuse.One end of the jumper to 12 volt. The 2 wire plug goes to the rear lights, jumper to them one at a time. On the 6 prong plug the white/blue and the green/white go to the front bulbs. Jumper 12 volts to them one at a time. One bulb should light each time you jumper12 volts to a plug pin.

Good LUCK

Rick don't know if this will help you or anyone else. The online prints for 65-66 Mustangs don't show clearly how the turn signal works, so I made this print. If anyone finds something wrong with this please let me know.

Last edited by wsinsle (5/15/2013 4:48 PM)

Rick you are absolutelly correct, numbers crossed, sorry for the confusion. The white/green wire sounds like the problem, the brake lights work so probably not rear. The problem seemed to be in  the left side and white/ green is the letf front. TRY THIS: Plug in the 2 conductor plug at the steering column, this goes to the rear. Lights will blink faster with just rear lights .Plug in the 6 connector plug. Unplug connector at fire wall. (I think MS or some one said front turn signal goes through this plug) Try the turn signa ifl the short seems to appear the problem is between the 6 prong plug and fire wall plug. If not problem between fire wall plug and head lights. Or you can try the same check with the ohm meter.

CORRECTED DIAGRAM

Last edited by wsinsle (5/16/2013 4:33 PM)

There are two spring loaded contacts in the bottom of the bulb base.  If one pops out when you remove the bulb, you will experience what you found.  Usually they can be inserted back into their sockets so the bulb can be installed.  If they won't stay in there, grab the wires behind the bulb socket and put some tension on them to overcome the spring pressure until you get the bulb in.

The courtesy lights under the dash only have one contact, and they are real bad about that issue as well.

Glad you figured it out.

It is always something simple.

Picture of the problem.

The brown wire is the ground and is attached to the copper split ring contact.  This provides the ground the bulb base.  Somehow, the blue turn signal wire engaged the grounding ring (defect or over charging?) resulting in the short.

I'm back.

Bought a new turn signal / parking light fixture.  Took it back because it was defective - poorly assembled (got to pay more attention when I pick parts up at the store).

Exchanged that light for another and on this one you need to hold bulb in tightly for it to light.

While testing with the replacement light we also noticed that we no longer have a dash turn signal indicator light.  Bulb looks good. Used to work both sides, then one side only, now neither side works.

Brake lights - good.
Rear Turn Signal - good (but blinks faster than it probably should)
Headlights / taillights - good

Parking "lights" - good?

I noticed on both front parking lights, when turn signal only is activated, the dim filiament is lit. With the parking light on it is very bright and you can hardly see the turn filament blink on and off. I seem to recall that this was like this when I first installed and tested my electrical and before I had any electrical issues.  Shouldn't this be the other way around - brighter with the blinker, dimmer with the parking light?

I am thinking that either the turn signal fixtures are wired backwards or the headlight harness is wired backward.  Should I cut the headlight harness and reverse the wiring? Where would be the best place to do this - inside the engine bay or underneath at the lights (two splices required)?

Really frustrating!

Unplugged the front lamps, rear lights blink - no dash board signal.

I think I have this figured out (finally).  I believe a part of my problem is / has been poor quality replacement parts (though if given a choice between good, better & best, I always choose best).  I fiddled with the turn signal switch and I finally got everything to work consistently at the moment.  However, if I wiggle the TS switch a little it may just stop working.  It is also intermittent so sometime when I wiggle it no problem.  Sometimes when I wiggle it, doesn't work.  Will try to find a better quality switch if possible. Bought the best repop part NPD has to offer.

I also noticed that the die cast steering column collar that the TS switch is mounted to is broken where the metal pin for the TS switch lever is mounted.  Need one of these collars if anyone has one to spare.

Thanks for everyone's help.  If I ever get to a bash, I owe a round.

MustangSteve - I sent you a private message. Rick

6sally6 wrote:

To add to the confusion........
WYIT you can jumper the taillight connection(on the headlight switch) to the front parking light connection.. This will give you front parking lights that burn when the headlights(and tail lights) are on. Kind of a cool mod to do on these older cars.
As you know....when the headlights are pulled on....the factory set-up makes the front parking lights go off.
I mean.....you got the headlight switch out anyhow!......
6sally6

Someone here - JamesW ? had a diagram that Bradster had posted a few years back with that headlight switch mod on it.

Actually - found it here: http://mustangforums.com/forum/classic-mustang-general-discussion/574306-how-to-wire-parking-lights-to-stay-on-with-headlights.html

Last edited by Ron68 (5/24/2013 5:47 PM)