04 Silverado 2500 Crew lights problem

Folks,
Can anyone shed any light (pun intended) on an intermittent problem I'm having with my truck? When the truck was only a few weeks old this first
appeared: With the lights on, the signals will both come on with the brake lights(this includes the mirrors). If you put the hazard lights on the high mount brake light, the brake lights, tail lights and the license plate lights all flash. If you use the turn signals one at a time they will flash once and stop with the lights (both sides) staying on weak. When it first happened it only lasted for part of the drive that night and never happened again until last night. I mentioned this to a GM tech friend of mine soon after the first time. He said he had not heard of any similar problems on other trucks, but if it reoccured to bring it in. The thing is, it goes away before I can bring it in. An electrical problem is difficult to diagnose if it doesn't exist at the time it is being looked at so I don't want to waste anyones time bringing it in until it persists.
Anyone seen this before? I'd like to get this resolved before I head out on a trip this coming weekend.
2004 Chevrolet Silverado K2500 Crew Cab LT
Rick.
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Don't have this on my '04 and never heard of it either, but it sounds like your flasher module is shorted or wired in wrong. The first and easiest thing to is to change the turn signal flasher relay. The only other thing I can think of is a crossed or grounded wire in the trailer wiring harness. Since it's an intermittent problem, it sounds like a shorted wire somewhere.
Good luck - Jonathan
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Jonathan A. Race
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On a taillight setup where a dual filament bulb is used, the bulb might not be installed properly which could backfeed voltage into another circuit. This kind of sounds like what is going on. I've seen it on my sister-in-law's Galant but I'm not sure the Silverado uses dual filament bulbs. On her car, it was the kind that you push in and turn 1/4 turn to install. Well her husband only turned it about 1/8th so when the parking lamps were on, the brake lights (including the third brake light) were on too. Something like this might be going on between the parking light and turn signal/hazzard circuits. I'd pull the tail lights and check those bulbs first.
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