2000 Silverado 2500 - no power to trailer related fuses in main fuse panel

[Mississippi Mike]

I am a new member on this great GM-Truck site and have an issue with a recently purchased truck. It is a 2000 Silverado 2500 with the Z82 trailer package. This work truck has apparently been run hard and put away wet all of it's life with 160,000 miles on the odometer. I purchased as a farm truck and don't intend to make it a show truck. It runs well (after replacing the Mass Air Sensor and air filter) and will serve my purposes to use around my property. I don't intend to put this truck on the road, however, I would like to be able to pull my 25' camper to local campgrounds on occasions. 

 

I tested the factory installed 7 way trailer connection and found no power. I opened the 12 volt main fuse panel under the hood and found no power to any of the trailer related fuses. See attached photo of fuse legend. Yellow highlight are the dead fuses. I pulled each fuse individually and checked with my multi-meter to confirm continuity. I removed the surrounding plastic cover from the under hood fuse panel and both  stud 1 and 2 are powered. All of the large fuses along the top of the panel are powered. 

 

The truck came with an aftermarket trailer brake controller and it is plugged into the under dash panel in the second from the left top plug in. There appears to be no power to the brake controller. I am going out this morning to continue my testing of the trailer circuit. I need to discover if the wiring is shorted or open. 

I guess my main question is this: What powers the trailer related fuses in the main fuse panel under the hood. It is interesting that the windshield washer pump and horn are operable even though those fuses indicate that they are dead. 

Any assistance will be greatly appreciated. 

[Jsdirt]

First thing I'd check is the battery cables, and any big fuses coming off that. Sounds like half the box isn't getting power at all. If that checks out, that power distribution box could be junk (underneath), or you got a mouse that chewed through wiring  under there or in the harness as well. 

 

Since you're far from the salt belt, my money is on a wiring issue. I'd grab a wiring diagram from AllData DIY (about $15) and see what, if any, common connection is between all those separate circuits. It'll save you a TON of headaches. 

Edited September 2, 2021 by Jsdirt

[Mississippi Mike]

thank you for your assistance. I will order the wiring diagram and go from there. Yesterday, I again removed the plastic surround on the under hood electrical distribution center. Checked all fuses again. I released the top fuse section and took a look underneath noting no damage. Here is the super strange thing. 

I checked for power again at the 7 way trailer connector noting that the plug was really dirty.  I removed the factory wiring harness from the back side of the plug and cleaned the contacts. I now have power to the trailer plug but the issue with the dead fuses is unchanged. I am baffled. How can I have power to the trailer plug at the rear of the vehicle and all of those fuses testing open? The horn and windshield washer pump work well too and both of those fuses are open. I tested all of the fuses again and both indicate continuity with my multi-meter. 

I ordered a replacement trailer plug in to replace the old dirty (corroded) one. 

 

I will post the solution once I have this mystery figured out. 

Thanks again for your words of wisdom.