Question about 2004 Chevrolet Silverado 2500HD

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I have a 2004 chevy 2500hd and the left trailer brake light went out the other day. The turn signal works fine and so do all the other lights on the trailer and truck.. I checked the bulb and all the fuses everything was fine. I tested the wire on the trailer and truck and at the pin it showed no juice running for the left brake light. I have been reading a little bit and I want to try to fix it myself to save $$$, but i read it may be the flasher module...?? Is this true and how would I get to it.. I know its under the dash but where? Thanks for any info......

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Brake lights don't usually run power through a flasher. I suggest that you turn on the parking lights AND the hazard flashers so they are active at the same time. What you may have is a missing ground on the light that is not working. Wiggle the wiring harness while both the parking lights and hazard lights are on. You might just find your intermittent/bad connection that way!

Posted on Apr 28, 2017

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The flasher module looks like a little silver container usually plugged into, or somewhere close to the fuse block under the drivers side dash. It's about half the size of a prescription pill bottle. They're usually relatively cheap to replace. I would first make sure that you don't have a short in the wire from one end of the trailer to the other. The easiest way to do this is to take a 12 volt tester (about $12 at your local auto store) and test to make sure you're getting power to the trailer switch if the truck (someone will have to push the brakes for the light to come on). If you're getting power there, then hook up the trailer connection. Now go to the problem light and find the 4 wires that go into then back of it. Typically one wire is a ground (usually the black one), one is for turn signal, one is for brakes, and one is for running lights. With someone holding the brake pedal down, you can use the needle like tip of the tester pobe to gently dig beneath the insulation of the wire. You should be getting constant power on atleast one of the wires. You can sort out which wires are which by turning on the turn signals and finding the one that works intermittently, then do the running lights, and so on. If not getting power to the light you've got a break somewhere between the front and back of the trailer. If not getting power to the pin on the truck. You have a break in that line somewhere.

Posted on Apr 28, 2017

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Check your fuse. If that's not it, then check all your ground wires.

Posted on Apr 28, 2017

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Posted on Jan 02, 2017

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SOURCE: 2001 Chev 2500HD

Based on what you are saying I would look to see if there are any corroded or broken wires, and I would take a good look at the ground wires that are leading into each of your rear lites.
Sometimes a wire will look as though it is connected but in fact has corroded off inside of the connector.
If the trailer plug is an afterthought then I would carefully inspect each of the wires as some people use test lites that have to be poked through the insulation on the wire thus allowing condensation to get into the wire and corrode them.
At each point where two wires meet and where ever a wire go's into a connector or lite socket ( pigtail ) I would give the wire a little tug to see that it indeed is secure.
Also if you have a test lite then remove the lite bulbs and test to see if there is any power to the lite pigtail itself. I'm sure that you have physically checked each bulb itself. if notthis is rare but it does happen on occasions, a bulb will burn out and the filament in the bulb will drop down and across to the other filament on the bulb causing the lite to short out that particular circuit and this will only happen when that particular part of the circuit is powered. As I mentioned this is very rare I've only seen it happen twice in my career.
Good luck, and I hope that this info is helpfull.

Posted on Oct 14, 2008

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SOURCE: 2004 Chevy silverado 2500HD the left stop light not working

use a testlight turn on the LS light ground the test light touch the pin inside the lamp socket if it lights look for a bad ground if it does not check your fuses or, run a new power wire under your truck secured with zip ties from the switch

Posted on Apr 20, 2009

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SOURCE: 1997 Chevy Tahoe both turn signals stopped working

Sounds like the flasher unit to me. Normally the emergency flasher and turn signal are separate.

Posted on Jul 21, 2009

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SOURCE: where is the flasher module on a 2001 GMC 2500HD

its probably on the back of the inside fuse panel on the driver side. usually looks like a metal cylinder or a black plastic square box. all it is is a relay. should be easy to find.

Posted on Oct 07, 2009

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SOURCE: 2001 2500hd silverado no stop

How have you tested this? If you are just looking for the stop or brake light, you need to test by pressing the break and probing the same pin as the turn signals as the vehicle does not have separate brake and turn signals. However, If the problem is that you have no signal for the electric brakes on your trailer. You must have a brake controller installed. If there is one installed probe the blue wire coming out the back end of it and press the brake to be sure there is brake output. It is possible for a controller to go bad, and not output anymore.
I wrote an imformative article on diagnosing wiring problems. Click here to read.

Posted on Jan 13, 2011

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