Topic: Front running lights quit working - 1/6/07 Fixed

[rkellerjr]

Seems that my front running lights aren't working.  I have headlights, turn signals, emergency flashers, all tailight functionality works fine as well.  This is isolated to just the running lights on the front of my '75.  Now, recently I exchanged my engine harness and prior to that everything was fine.  What I don't remember is whether the lights were fine RIGHT after the install or shortly after the install.  So far, here's what I've done...

*  Checked fuses, had one blown but no effect
*  Pulled the harness block from the firewall, checked all pins, everything is fine, reinstalled and made sure it was secure.
*  Shaked the front harness wires to see if maybe I had a short.

Now, this includes both lights in the grill and the side markers.  Thoughts?

[ta78w72]

Have you checked the switch?  I don't have a 75 wiring diagram but on the 78 it's one of the brown wires that carries current to the headlights.  Also, check your ground wires.

[rkellerjr]

Forgot to mention that I did check the ground wire for the harness, it's intact but, I would think that would cause all lights to fail, not just the running lights.

[ta78w72]

I misread your post.  Now that I've reread it, I don't have a clue what you're talking about.  I don't know what "running lights" are.  Are you talking about the parking lights which are also the turn indicator lights?

You said you have turn indicator lights?  The turn indicator lights including the ones in the front grill and side markers.  Do they work when you turn the signals on? 

Do the parking lights and side marker lights come on with the first position of the headlight switch?  Do they come on with the second position of the headlight switch?  Are they always "Dead".

Those parking lights are grounded and my guess is the side marker lights get their ground from them too.  Try running a ground wire from the parking light to the frame and see if the lights work.

[Joker (§ir£Ðragon)]

Check the bulbs in the side markers. The front marker lights are wired a little weird in order to get the side lights to come on with the markers and flash with the turn signals while only having one element. If they are burned out it will play games with the other lights. For that matter so will any of the marker lights being bad or a bad ground. But those small bulbs would be my first thing I'd check.

Here's a wiring diagram.

http://www.autozone.com/images/cds/gif/large/0900823d8021731c.gif

[rkellerjr]

Running lights, parking lights, same thing.  The parking lights will not come on and that includes the side markers however, as I've mentioned ALL turn signals work as well as the hazard.  Which means that the parking light bulbs are flashing and the side marker bulbs are flashing.  Here's a vid, first I turn on the parking lights, then the headlights, then the turn signals, then the hazaards, then turn off the headlights with just parking lights, then off.

http://www.zenonline.com/~rkeller/2007vids/ParkingLights.wmv

[jphillips3333]

Check the bulbs - it's probably one or two.  Even though they may all blink, there is 'sposed to be a low intensity glow with just the parking lamps.  When my I turn on the parking lamps and hit the turn indicator on my '76, they come on brighter but the parking lamp intensity remains.

I also seem to recall a situation in years past where there'd be one on, burning a bit brighter, but they wouldn't blink.

[ta78w72]

Check the brown wire for 12 volt.  That's the circuit that's controlled by the switch.  The other circuits, the blinking, is done with the turn signal.  When you pull the headlight switch out to the first position, you should get those lights on.  Then the second position turns on the headlights so that both sets of lights are on.

How about the rear side marker lights, do those come on?  It certainly isn't the bulbs.  Unless all of them are bad....that would be six bulbs if the rear doesn't come on. Doubtful.

That leads me back to the brown wire.  You have a complete circuit when you're in the blinker phase, but no circuit when the headlight switch is pulled on.  That would suggest to me that you're not getting current down the brown wire....and if you're not getting the rear side marker lights on, it's my only guess.

See, you get current from two different sources, the blinker circuit and the headlight circuit.  The blue wires are for the blinker circuit.  I assume you get ground for both circuits off the black wire from the parking light.  But checking the brown wire is the first step, with the second step to ground the parking lights.

If you're not getting 12 volt down the brown wire, you need to pull the switch and check it with an ohm meter.

[Joker (§ir£Ðragon)]

Rich is really getting into the video thing.    That does help though. You're right, a bad ground would most likely cause issues with the t/s circuit as well.  

Ok, according to the wiring diagram all the marker lights, front, back, sides and lic. plate are all controlled by the brown wire from the headlight switch. At some point either under the dash or right at the bulkhead connector (I don't remember exactly where) it splits to go either to the nose or tail of the car. (Someone refresh my memory. I seem to recall some cars with a pair of wires coming off the same connector at the headlight switch also.) So we know it's ok up to that point. So the problem is in that wire up to the nose where it begins to split up to each individual bulb. Either in a connector or a break in the wire.

Have you been able to check for power at the lights or bulkhead connector?

[ta78w72]

There's a double brown on the interior section of the bulkhead connector.  There's another splice in the engine compartment to feed the four lights.  If the rear lights don't come on, it's most likely a bad switch, at least that's where I would start.  If the back side markers do come on, I'd start looking at the front light grounds, because the rear side marker lights are each grounded.

[Joker (§ir£Ðragon)]

There's a double brown on the interior section of the bulkhead connector.  There's another splice in the engine compartment to feed the four lights.  If the rear lights don't come on, it's most likely a bad switch, at least that's where I would start.  If the back side markers do come on, I'd start looking at the front light grounds, because the rear side marker lights are each grounded.

Wouldn't the front turn signals share the same ground as the front marker lights? Especially since they share the same 1157 bulbs?

He did mention in the first post that all his taillights are working.

[rkellerjr]

Rear lights work fine.  ALL lights on the car work as advertised EXCEPT the front parking lights. I do not think it's a bad switch however, I do have a brand new switch, I've just never installed it.  I couldn't figure out how to get the switch out of the dash after taking the bezel off.

[ta78w72]

Then we're back to ground....assuming you have the brown wire on the engine compartment side in the right slot so it connects to the proper spot on the interior bulkhead connector.

The rear lights working tell me that you've got 12 volt to the interior bulkhead connector (and that your switch is OK).  So, try grounding one of the parking lights and see what happens.  If still nothing, pull the engine compartment side of the bulkhead connector and check for 12 volts at the interior connector (which you should have if the rear side marker lights go on).  If you've got voltage, ensure that you've got the wire in the right slot.  Reinstall and check for voltage.  If you've got voltage, check for voltage at the brown wire of the parking light, if you've got voltage...you have a bad ground.  If you don't have voltage, those brown wires are spliced together.

At this point, I can only see two possibilities....a bad ground to both parking lights, or a wire in the wrong slot of the engine compartment bulkhead connector.  Get your volt meter out.

[ta78w72]

Rear lights work fine.  ALL lights on the car work as advertised EXCEPT the front parking lights. I do not think it's a bad switch however, I do have a brand new switch, I've just never installed it.  I couldn't figure out how to get the switch out of the dash after taking the bezel off.

Not really true...your front side marker lights aren't working right?

[rkellerjr]

When I say parking lights I mean all of the orange lights that should be on in the front, which includes the side markers and your right, they are not working as "parking" lights, just as turn signals.