2004 chevy silverado 2500 trailer light problem....?

[pav w]

I have a 2004 chevy 2500hd and my left brake light on my trailer went out the other day. The turn signal works fine on the left side along with all of the other lights on both the truck and the trailer. I checked the bulb and fuses and everything was fine. I also tested the wires on the trailer and on the pin on the truck, I came up with no juice at the pin on the truck for the left brake light going to the trailer, everything else tested fine even the left turn signal. So I know that the problem is with the truck and not the trailer. I have tested and tried everything. I also looked on the internet to diagnose it, and found a similar problem with the flasher module..? I'm not really sure on if that's what my problem may be or not and if so where is it..or what else could it be,I'm trying to save $ and learn a little by doing it myself. Thanks..
The problem is definitely with the truck. There is no power coming from the truck to the trailer. I tested the pins and wires, so the problem is in the truck and not the bulbs or wires on the trailer.. and its not the fuses in the truck either.thanks

 

[dick car guy]

go down to the auto parts store and ask them for a heavy duty turn signal flasher unit for your pickup, it is under the dash below the steering wheel and easy to unplug and plug in a new one. The heavy duty one looks the same, so buy one, and look under the dash, keep in mind, most vehicles have two flasher units, one for the turn signals, and one for the emergency 4 way flashers. If you buy one first, it will be easy to spot under the dash, the heavy duty flasher unit will last much longer, and be able to withstand the extra heat from the extra electrical connections on the trailer. This is a common problem, a stock flasher does not work long when a trailer is plugged in. lets hope this takes care of it.