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Discussion Starter #1
OK, I checked everything this weekend, as follows:

First, doesn't make any difference if headlights are on or off.

Front & rear parking lights work.

Left front turn signal does not work at all.

Both rear turn signals work.

With brakes applied, only right brake light works

With brakes applied and right turn signal on, left brake light works.

Basically, everything works except left rear brake light (unless right turn signal is on) and left front turn signal (but left front parking light works). Oh, yeah, the left turn signal indicator light in dash does not work.

There were problems like this when I got the car and my dad had a guy look at it and put in a new turn signal switch. Everything worked fine for a while. Dad replaced the front valence and that may have been when things started getting messed up.

So, wacha think. Thanks for any help you can give me.

andy
 

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I had a similar problem on my '66 coupe years ago, they failed my inspection because the left front turn signal didn't work with the high beams on, but worked any other time (I got it inspected elsewhere.)

I don't think you are going to find an easy solution. I bought the wiring diagram for my car, $6, and started tracing things out and testing. I found all kinds of anomalies behind the dash, bad grounds, back feeding circuits, replaced wires, melted wires. I decided to replace the turn signal switch (since it was in bad shape) and straighten everything else out as best I could. I never pinpointed the exact cause of the problem, but it went away with straightening out the mess behind the dash.

Wish I had a simpler solution, maybe someone else will.

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Jason
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I'm an electrician, lemme put my $.02 in. I think you may have several things going on getting mixed into the equation. 1st, I think you're on the right track with the new valance, recheck any connections to the front socket(s). Check the contacts inside ALL the sockets, front and rear. What happens, lead is used on the ends of the bulbs and oxidizes causing poor connections. When you loose a ground connection on a bulb with multable filiments, you get strange things going on ( current tries to and does find another path to ground and things that aren't suppose to work, do ) this is why you'll see a car with one dull headlight and one bright one.

When I do trouble shooting, I look for the simple basic stuff first. Check all sockets, bulbs first before you really start to dig into anything major. Get back to us.

Tom
You can do anything you want to......ONCE!
aka "my 66 coupe"
 

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I'll have to complete this tonight when I can consult the wiring diagram, but at least I know that the left front turn signal is bad...probably the bulb. There is an interaction between the brake light signal and the turn signals, which indicates a cross-filament or wire somewhere.

Good information, here...I just need to know which filament works off of which signal, and I don't have that information memorized....check back around 6PM CST.

http://clubs.hemmings.com/baymustang/platesmall.jpgLet me check your shorts! My multimeter is just a-waiting! Formerly known as Midlife in the old VMF.
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Discussion Starter #5
Thanks, Midlife. I won't be able to check back with you until in the morning. I don't have a puter at home. Sure would like to get this stuff straightened out, though. Thanks, again.

andy
 

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Left front turn signal not working may also be the ground for that lamp. Check both sides, run continuity from the case of the parking lamp to chassis ground. I had a problem where the light would sometimes work, but the dash indicator didn't work. Good luck...



Steve Leslie, 65 coupe in restoration. 302, toploader, A/C, disc brakes, bench seat

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OK. Headlights run one filament; brake and turnsignals share the other.

Left front bulb is bad, base not grounded, or signal line disconnected.
Since left turn signal works w/o brakes, that says that turn signal voltage is reaching each filament.

Now that is interesting that the left brake doesn't work, but the turn signal does. They share the same line coming out of the turn signal switch, so that has to be bad. Input for brake is shared between left and right in the turn signal switch, so we can rule brake input out.

Left turn signal indicator won't work because the left front bulb isn't lighting up...that's the indication that you have a bulb out.

With brake on, right turn signal on, left brake light works (I presume the left blinks). This indicates the left/right might be swapped, but then you say the turn signals work fine without the brake. I say there is something wrong in the turn signal switch behind the steering wheel.

When you replace it, tie a string around the wires that you will draw up through the column, so you can snake them down again. Also, put a piece of black electrical tape behind the switch, as the rivet heads may contact the metal backing piece, which is ground.

I say replace the turn signal switch, and the left front bulb.

http://clubs.hemmings.com/baymustang/platesmall.jpgLet me check your shorts! My multimeter is just a-waiting! Formerly known as Midlife in the old VMF.
King of the Old Farts *struts*
 

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Regarding replacing the turn signal switch, if the old one is busted and being tossed, cut off the wires (leaving them in the steering column) and tie one of the cut wires to the new wires of the new turn signal switch. Pull the old wires out and pull the new wires into place. Voila! No have to look for string which I wasted two hours doing when I replaced my last turn signal switch.

The Zog award goes to Kurt67 who posted the no string method of replacing turn signal switches.

Regards,

Dean T

Shikatta Ga Nai - "It cannot be helped"
 

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A most excellent idea! Why didn't I think of that?

http://clubs.hemmings.com/baymustang/platesmall.jpgLet me check your shorts! My multimeter is just a-waiting! Formerly known as Midlife in the old VMF.
King of the Old Farts *struts*
 
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