Author Topic: Trunk light quit working  (Read 2005 times)

Offline BillEBobb

  • Full Member
  • ***
  • Posts: 108
Trunk light quit working
« on: July 02, 2012, 10:55:03 AM »
**Not your "typical" concours-type question, but I got no help on VMF.***

I can't figure out what's going on. Trunk light had been working then quit. 
First off:
• Bulb tests okay • Mercury switch okay • wiring tests okay
Here's where it's at:
• Test light shows link from fuse box is not hot (no electricity) -- yet everything else on same circuit works -- so it's not the fuse.
NOTHING has been disturbed, no chance of a break or a screw into the wiring harness, etc., etc.

I'm thinking about putting a tone generator onto the wiring bullet over the wheelwell and running a detector across the run.

Other than that I'm at a loss.

Anyone else have a mysterious trunk light outage? lol

Suggestions?

Thanks, Bill


Offline Bob Gaines

  • Global Moderator
  • Hero Member
  • ****
  • Posts: 9001
Re: Trunk light quit working
« Reply #1 on: July 02, 2012, 06:52:33 PM »
**Not your "typical" concours-type question, but I got no help on VMF.***

I can't figure out what's going on. Trunk light had been working then quit. 
First off:
• Bulb tests okay • Mercury switch okay • wiring tests okay
Here's where it's at:
• Test light shows link from fuse box is not hot (no electricity) -- yet everything else on same circuit works -- so it's not the fuse.
NOTHING has been disturbed, no chance of a break or a screw into the wiring harness, etc., etc.

I'm thinking about putting a tone generator onto the wiring bullet over the wheelwell and running a detector across the run.

Other than that I'm at a loss.

Anyone else have a mysterious trunk light outage? lol

Suggestions?

Thanks, Bill
You may find that something HAS been disturbed just something you are not aware of.  It sounds like you are taking the right course of action and tracing down the wire from the fuse box to the back. I would test it at the rocker and if you have voltage there l would test a section from the wheel well back to the light for continuity and if that back section proves out then just run another line splicing in at the rocker hidden from view and connect at the wheel well  again hidden from view and be done with it . The break is somewhere between the front and back and it will take less time to replace the whole section then try and narrow the exact place down. You may want to find the exact mystery and more power to you if that is you but for most they just want the frustration to stop as soon as possble.You may also find the faulty area in your testing and splice between the fuse box and the rocker or between the wheel well and the light with appropriate wire or remnants from another wire harness. I keep remnants around for repair purposes. This may not be the answer you want but if all is as you say this procedure will solve your problem one way or the other. The best of luck with your search.
Bob Gaines,Shelby enthusiast, Shelby collector , Shelby concours judge SAAC,MCA,Mid America Shelby

Offline midlife

  • Wiring Guru---let me check your shorts!
  • Global Moderator
  • Hero Member
  • ****
  • Posts: 2158
    • Midlife Harness Restorations
Re: Trunk light quit working
« Reply #2 on: July 02, 2012, 09:35:24 PM »
You may find that something HAS been disturbed just something you are not aware of.  It sounds like you are taking the right course of action and tracing down the wire from the fuse box to the back. I would test it at the rocker and if you have voltage there l would test a section from the wheel well back to the light for continuity and if that back section proves out then just run another line splicing in at the rocker hidden from view and connect at the wheel well  again hidden from view and be done with it . The break is somewhere between the front and back and it will take less time to replace the whole section then try and narrow the exact place down. You may want to find the exact mystery and more power to you if that is you but for most they just want the frustration to stop as soon as possble.You may also find the faulty area in your testing and splice between the fuse box and the rocker or between the wheel well and the light with appropriate wire or remnants from another wire harness. I keep remnants around for repair purposes. This may not be the answer you want but if all is as you say this procedure will solve your problem one way or the other. The best of luck with your search.
+1.  The wire color in question is green/yellow, and is directly traceable to the fuse box.  The two ends of the green/yellow circuit is the fuse box and the right hand side door jamb.  The plug for this trunk light is intermediate between these two points.  I have often found that dual wire female bullet plugs fail on one side such that resistance is increased at this point.  The quick test for this is to open the right hand door and see if your courtesy lights activate, as these lights (black/blue) depend upon the green/yellow circuit for their power.  If the courtesy lights work, then you should have power at the main harness.  Then, tracing the voltage as suggested above is an excellent approach.
Midlife Harness Restorations - http://midlifeharness.com

Offline BillEBobb

  • Full Member
  • ***
  • Posts: 108
Re: Trunk light quit working
« Reply #3 on: July 02, 2012, 11:01:24 PM »
Thanks guys!  When the car comes back from the paint shop (touching up boo-boos caused when re-fitting hood --  >:( ) I will certainly employ your suggestions!

Thanks again,

Bill

Offline Carl

  • Jr. Member
  • **
  • Posts: 53
Re: Trunk light quit working
« Reply #4 on: July 03, 2012, 01:57:31 PM »
Did you check the ground?  IIRC, the power lead is a single, ground is from the lamp body to the trunk lid. If the connection to the body is dirty or corroded, no light.  With the light installed, check the path from the light housing to the body (stud head for taillights?)
Yes, I know you said the lead is not hot, but stranger things have happened to me.

  Carl
« Last Edit: July 03, 2012, 01:59:13 PM by Carl »