Headlight diagnostics P15

[MaineP15]

My headlights do not currently work.

I have been trying to diagnose the issue.

I have done the following:

1) The headlight is ok.

2) I have voltage all the way to the high/ow footswitch, and no voltage across. 

3) I jumped the wires across the footswitch to eliminate the switch. and verified the voltage is present on the other side..Nothing.

4) The ground is ok.

5) the battery is brand new, so I have full 6 volts

 

I am probably missing something in the diagnostics.

[Grdpa's 50 Dodge]

was your jumper wire on the foot switch too thin?  To carry enuf current? was it connected tightly enuf?  If all was fine must have a broken connection thru the switch to front of car area.  Is there a firewall safety connection box with a relay in it?

[Bmartin]

Take your meter and go to the next step in the wiring chain.  Most likely there is a terminal block under the hood, see if you have voltage there with the jumper wire on.  Could be a bad connection or spade lug.  If you've got enough jumper wire, you can work through the system bypassing each piece in the chain,  step by step.  Electrical issues can be frustrating.  I like to make a photocopy of the wiring diagram in my manual and check things off with a red pen. 

[_shel_ny]

Voltage at the terminal block up by the radiator?

 

Headlights/grounds verified good by running a wire directly from the battery to the terminal block?

[suntennis]

Your dimer switch should have power on two terminals anytime the head lites are turned on. If there is only power at one terminal, then there is a problem with that switch.

[MaineP15]

Thanks for the responses.

Yes, i have grounded the whole thing direct to the battery.

I think there is a break in the wire somewhere between the foot switch and light, in addition to a bad foot switch.

As for the light switch, on the running light selection (half way out) there is power to one terminal, and all the way out (headlights) there is power to a different terminal.

More diagnostics is in order at this point, thanks for the input!!!!!

Aside: I bought a new battery today, and wow, what a difference, the other battery I had was cooked. So any starting issues I had were battery issues.

[greg g]

Your switching is correct one terminal on the headlight switch is for the parking lamps, unlike newer cars they are off with head lamps out.  With the dimmer switch one terminal is for high bean and one for low so it should be one in and two out with only one powered at a time.  Bypass the switch by connecting the power in wire to one of the power out terminals.  That should at least get you power to the terminal block at the radiator support.  If that works until you replace the dimmer switch at least you can wire up low beams.  

 

Remove the dimmer switch and bench test it with a 6 or 12 volt power source the switch won't care about voltage or polarity as you test it  Do you have a lighted circuit test probe??

 

Have you cycled the dimmer repeatedly?  They tend to get corrosion on the contacts and may time repeated rapid working of the switch will clean the contacts.

Edited October 13, 2013 by greg g

[MaineP15]

Hello greg,

thanks,

yes I did some searching and reading, I cycled the foot switch a bunch of times, I told my son I was replicating 65 years of driving use!

i tried to jump the switch, but it did not work, perhaps my jump was shoddy. Although I read 6V at the out wire, maybe I was touching the known good hot wire in tandem without knowing, its a long reach down there.

One question: from the out wire on the foot switch, does the wire merely go straight to the terminal block, then to the lights? i.e. it doesnt pass through anyplace else correct?

To all, thanks for all the help, this forum is AWESOME!

 

THANKS!!!!!

[greg g]

Some might go to a relay after the switch but I would think the majority went from dimmer out to terminal block.

[MaineP15]

I need a new dimmer switch and 2 new headlights. Got a good jump finally across the switch. Test light lights and multimeter reads 5.7 V at the terminal block, and headlight plug...  1 headlight I blew during diagnostics, and the other one must be no good as it did not light. I know the ground is good.

So.... a dimmer switch and 2 new headlights.

The switch is not overly easy to jump, esp. when you leave the wires in situ.

[desoto1939]

You will use a 6Volt headlight bulb 6006 if I remember correctly.  This year I saw more that I ususally do at Hershey.

 

Rich HArtung

desoto1939@aol.com

[greg g]

While you are at it make sure the ground wire from the headlamp socket goes to a good ground.  The wire attaches to a spot that is directly in line with where the tire throws up road slop.  I cleaned my grounds a couple years back and it made a significant improvement in head lam performance.

[bamfordsgarage]

You will use a 6Volt headlight bulb 6006 if I remember correctly.  This year I saw more that I ususally do at Hershey.

 

Rich HArtung

desoto1939@aol.com

 

I suggest the H6006 halogen version — direct replacement and superior illumination. The NAPA in Honolulu had them on the shelf.

[greg g]

Probably can't beat this price.

 

http://autoplicity.com/products/3591628-wagner_lighting_h6006.aspx?utm_source=google&utm_medium=cpc&utm_content=3591628NOFITMENT&utm_campaign=GSNOFITMENT&adtype=pla&kw=&utm_term=&adpos=1o3&network=g&gclid=CJuhxtqgmroCFYWe4AodtF4AmQ