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Old 09-01-2013, 06:10 PM   #1
SCHRUMGMC
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Wiring Question

Alright my Back right brake lights don't show up and neither do the back Red side-markers..As I was looking under my truck I noticed a Red wire looked like it had been cut off


Help please !!!
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Old 09-01-2013, 07:43 PM   #2
JimKshortstep4x4
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Re: Wiring Question

No red wires were used on the rear lights. There is a four wire flat harness going from the front to the rear lights. Light green: backup lights, dark green: right rear turn signal, brown: park lights, tag light, and trim light, yellow: left rear turn signal.

Brake lights work through the turnsignal circuits.

Jim
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Old 09-02-2013, 08:45 AM   #3
midniteblues
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Re: Wiring Question

check too make sure the rear light assembly has a good ground.

check inside where the bulb goes too make sure the contacs for the bulb are present and not broken off.

i like too use a long wire that has alligator clips. one side goes too the battery ground.

take the lens off the light and sand/scrap a clean bare spot of metal on the light houseing. touch/clip the wire too the spot and test your light.

if it works you'll need to take the two screws out that are next too the bulb

and clean up the spot around the two screws where the back of inner light houseing touches/mounts too the bed. this is where the ground is.

of course you should have a test light. with it you can check the bulb socket too see if it even getting juice.if its not then you need too keep testing the wire.

the rear harness has connectors too the lights in the rear bed sides pull them apart an test.(if you do this they prolly should be cleaned up an greased anyway.

still nothing?

in the last frame crossmember theres round plug with the four wires that go through the metal. pull the rubber peices apart an test from here also.(jim pointed out witch wires too test)

if all else fails

buy some new bulbs
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Old 09-02-2013, 09:02 AM   #4
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Re: Wiring Question

Quote:
Originally Posted by midniteblues View Post
check too make sure the rear light assembly has a good ground.

check inside where the bulb goes too make sure the contacs for the bulb are present and not broken off.

i like too use a long wire that has alligator clips. one side goes too the battery ground.

take the lens off the light and sand/scrap a clean bare spot of metal on the light houseing. touch/clip the wire too the spot and test your light.

if it works you'll need to take the two screws out that are next too the bulb

and clean up the spot around the two screws where the back of inner light houseing touches/mounts too the bed. this is where the ground is.

of course you should have a test light. with it you can check the bulb socket too see if it even getting juice.if its not then you need too keep testing the wire.

the rear harness has connectors too the lights in the rear bed sides pull them apart an test.(if you do this they prolly should be cleaned up an greased anyway.

still nothing?

in the last frame crossmember theres round plug with the four wires that go through the metal. pull the rubber peices apart an test from here also.(jim pointed out witch wires too test)

if all else fails

buy some new bulbs
Start with the last suggestion first...burned out bulbs and fuses have cost me countless hours of troubleshooting over the years...you would think I would learn.
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Old 09-02-2013, 09:05 AM   #5
lolife99
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Re: Wiring Question

Any time you can post pics with your questions,... it would be very helpful.
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Old 09-02-2013, 09:24 AM   #6
SCHRUMGMC
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Re: Wiring Question

Alright I will today, I dont have anyway of getting the fuses out ?
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Old 09-02-2013, 10:05 AM   #7
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Re: Wiring Question

They usually pry right out...use something non metallic...if they have been in there for 40 years they may be a little sticky, but the are just held in by thin metal tabs squeezing the fuse ends.
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Last edited by slow-1; 09-02-2013 at 10:12 AM.
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Old 09-02-2013, 10:13 AM   #8
SCHRUMGMC
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Re: Wiring Question

But what if they break in there ?
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Old 09-02-2013, 10:18 AM   #9
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Re: Wiring Question

Pull out the ends with needle nose pliers and put in a new one.
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Old 09-02-2013, 02:17 PM   #10
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Re: Wiring Question

Oh ok well that was simple, how do I know if my points are bad ?? It wants to start but it won't' and it cut off while driving it on me
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Old 09-02-2013, 02:24 PM   #11
Tom Vogel
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Re: Wiring Question

Your points are probably fine. Check/replace your fuel filter.
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Old 09-02-2013, 02:26 PM   #12
GASoline71
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Re: Wiring Question

Lots of old trucks have messed up rear lighting because of prior owners hacking up the rear harnesses to wire in trailer lights and such. I've had to rewire the entire rear ends of trucks because of it.

Gary
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Old 09-02-2013, 02:30 PM   #13
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Re: Wiring Question

I just put a new fuel filter in there,,I wonder
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Old 09-02-2013, 07:07 PM   #14
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Re: Wiring Question

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I just put a new fuel filter in there,,I wonder
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It may already be plugged. Is there crap in the tank maybe?
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