Expert Answers about GMC Sierra

• Troubleshooting Pins of 7-Way at Rear of 2003 GMC Sierra that Arent Active
• First thing I would try is unplugging the 7-way you have installed in the bed of your truck. Unplug it from the 7-way that is at the rear of the vehicle and then connect the rear 7-way back up without the harness to see if that allows the pins on the 7-way to be active again. Under your hood there would need to be some connections made. I attached a help article that covers that info for you to check out. The fuses could also be blown. Also, you can try checking the pins of the 7-way in...
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• Trailer Brakes Only Working With Manual Override on 2011 GMC Sierra
• If your trailer brakes are only working when you apply the manual override the issue is commonly the red wire - the stop light switch. Make sure it is connected to the circuit that that only sees voltage when the brakes are applied. The issue with not displaying numbers does make me think that the brake controller may have hit the fritz and need to be replaced though, and this would be true if the numbers never display, even when using the manual override. For your 2011 GMC Sierra a great...
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• Troubleshooting A Clunking Noise Between A Fifth Wheel Hitch And Base Rails While Towing
• It's totally normal for a bit of movement between any fifth wheel hitch and the base rails. The feet on the hitch are typically a bit smaller than the slots they slide into for mounting otherwise you'd have a hard time getting your hitch in or out of the base rails. This does cause a bit of noise and would allow you to pull up on the hitch slightly. If you're getting a lot of movement then it leads me to believe that either an incorrect sized pin is being used to mount to hitch into the...
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• Troubleshooting Hopkins Agility Brake Controller Install on a 2005 GMC Sierra 1500
• I have linked an installation video below for a Tekonsha Prodigy P2 # 90885 installation on a similar 2003 Silverado 1500. The process is identical to installing a Hopkins Agility Trailer Brake Controller 42794 with the Adapter HM47795. It sounds like you connected the power wire for the charge line and not the 2nd power wire for the brake controller.
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• Troubleshooting Trailer Brake Magnets With Wires Cut Short and Inside of Brake Assembly
• If the wires are cut to short and are inside the assembly, you can make the connections inside using the Deka Heat Shrink Butt Connector - 12-10 Gauge - Nylon Insulation - Yellow - Qty 5 # DW05745-5 to ensure a good connection. If you don't have enough movement behind the brake magnet spring assembly for the connections, then I recommend replacing the magnets so you will have appropriate function. For 10 inch assemblies use # AKBRKR-M10 or for 12 inch assemblies use # AKBRKR-M12 or #...
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• Troubleshooting Left Side Trailer Lights Not Working
• If just the left side of the lights on your trailer are not working, then there is likely an issue with the wiring on that side of the trailer. To be sure that the issue is on the trailer side, and not on your Sierra, I first recommend using a circuit tester like # PTW2993 at the 7-Way on your truck. Test the left turn/stop circuit on the connector (pin at 9 o'clock position) to see if you get power there with that function activated on the truck. If you do get power, then you know the...
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• Troubleshooting Brake Controller Installation On 2003 GMC 3500
• When checking the brake output circuit of a 7-Way there should not be 12 volts of power all the time. A Curt brake controller will have what is termed 'dead' voltage at idle. This means there is voltage but no amperage draw. You can test for amperage instead of voltage to see if that is the case. If so, then you do not have a problem. If you are showing amperage draw that would indicate a short somewhere or possibly a problem with the brake controller. For a Curt brake controller, and if...
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• Troubleshooting Trailer Brake Controller on 2003 GMC 2500HD Sierra 4x4
• When troubleshooting the brake controller on your 2003 GMC 2500HD 4x4, I would first start out by using a circuit tester like part # PTW2992, to ensure that the red wire coming from the brake controller has power when the brake pedal is pressed. If the red wire does not have power, a problem most likely exists with the wiring harness or somewhere on the truck. If the red wire does have power, then you most likely have a faulty brake controller, and it will need to be replaced. In this...
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• Troubleshooting Weak Trailer Brakes on a Toy Hauler Even After New Axles
• This could be a magnet wiring problem. It is unlikely that the magnets are bad on new assemblies, but if the wiring is not properly connected, it could cause problems. Check to see that the magnets are properly grounded to a clean, bare metal surface free of corrosion. A bad ground would not allow the circuit to be complete and lead to the brakes not performing like they should. You can also try running all of the brake grounds back to the main ground of the trailer. The new brake assemblies...
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• Trailer Lights Not Working On Multiple Trailers With 2005 GMC Sierra 1500
• It definitely sounds like an issue with your 7-way connection or the wiring that leads to it on your 2005 GMC Sierra 1500 Z71. I recommend using a Circuit Tester # PTW2991 to begin checking the poles of the 7-way on your Sierra. First make sure to check your fuses and relays that are under the hood and in the cabin for any that are damaged. The circuit tester can help with that task as well. Once all the fuses and relays are checked begin checking the poles on the 7-way. If you find...
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• Troubleshooting Running Light Function on Trailer with 2008 GMC 1500
• For your 2008 GMC Sierra 1500, I do recommend checking the running lights pin on your 7-way. That will let you know if there is a trailer issue or a truck issue. This pin is located at the 11 o'clock position. There is a trailer park lamp fuse #25 in your underhood fuse block. If that checks out, then you will want to check the function of your lights you can simply connect a jump wire to each wire for function. It is possible that your 3 wire lights could use that grey wire as a running...
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• Troubleshooting Tekonsha Primus IQ That Got Wet and Locks up Trailer Brakes
• Since your trailer brakes are locking up after the Tekonsha Primus IQ Trailer Brake Controller # TK90160 got wet it is highly likely that you will need a new unit as it has likely gone bad but you can test this. To test the brake controller, sever the blue wire a couple inches from the back of your controller. Then use circuit tester # PTW2979 to test the end of the blue wire coming out of the controller. It should only have power when you apply the manual override; if it shows power at...
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• Troubleshooting Brake Controller When Trailer Brakes Dont Apply Unless Manual Override Is Used
• It sounds like there is an installation issue or a short in how your brake controller is connected. Since you have the manual override, it is likely that your brake controller is not malfunctioning. It sounds like the red wire from your brake controller that should be connected to your tail light switch either isn't connected or has a short. I recommend using a circuit tester like # PTW2993 to test that tail light wire for function. It should be giving a signal on the cold side when...
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• Troubleshooting Brake Controller not Working on 2006 GMC Sierra
• There are a number of troubleshooting steps you can undertake in order to try and determine what the issue is with the brake controller on your 2006 GMC Sierra To test the brake controller itself, sever the blue wire a couple inches from the back of your controller. Then use a circuit tester such as # PTW2979 to test the end of the blue wire coming out of the controller. It should only have power when you apply the manual override; if it shows power at idle then there is an issue with...
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• Power Level Jumps Up with No Trailer Connected to a 2004 GMC Sierra and Primus Brake Controller
• The most likely cause of the power jumping up on the brake controller with no trailer connected is a dirty or corroded vehicle side trailer connector. Check the connector on the truck and make sure it is clean and free of corrosion inside, where the wires attach, and outside on the pins. What can happen is corrosion will cause electricity to jump from a nearby pin to the brake pin drawing power and causing the brake controller to display output voltage.
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• Troubleshooting Red Flashing Light on the Curt Venturer Trailer Brake Controller # C74VV
• If you check out the picture that I attached you can see that your Curt Venturer Trailer Brake Controller # C74VV that you installed is detecting an overload or short on the brake circuit of your 2008 GMC Sierra. The wiring adapter # C51515 that you also installed is the correct adapter so now we need to determine if the problem is on your Sierra or your trailer. If you have another trailer with brakes handy then you can simply hook up to that trailer and see if the same thing happens. Whether...
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• Troubleshooting Brake Controller Causing Running Lights to Go On
• Start by testing the 7-way on your truck, because the only pin that should be lighting up when you apply the manual override is the pin in the 5 o'clock position, which is the brake controller output wire; there should not be power to the running lights, which is the pin at the 11 o'clock position. If there is, you know something has been mis-wired somehow. Also check your wiring thoroughly to ensure there are none that are crimped, broken or otherwise damaged. Also, corrosion or dirt...
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• Brake Controller Fully Engages Brakes on Trailer Jerking Truck Back
• It sounds like your brake controller gain is set to high and needs to be turned down. Be sure to check your owners manual on how to turn the gain down. If this does not help or you have a proportional brake controller be sure that it is mounted correctly as they sometimes are required to be mounted at a certain angle in relationship to the vehicle. Lastly the brakes on the trailer may be out of adjustment. You can use a Brake Adjustment Tool # W80630 to adjust them. See the linked article...
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• Toubleshooting Trailer Lights Not Working When Brake Pedal is Pressed
• It sounds like you have a ground issue. You can use a circuit tester, like # PTW2993, to determine if the issues is on your vehicle or on the trailer. Using a circuit tester, you can test the pins on your vehicle connector to ensure they are all working properly. Another option is to hook the trailer up to another vehicle with properly functioning wiring to see if the trailer lights work properly. If the trailer lights work with a different vehicle or the circuit tester shows your vehicle...
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• Should Weight Distribution Head Be Replaced If Bent
• It is rare that we hear of a weight distribution head being bent as you described. It possibly could have been caused by the head not being tightened if the angle was changed. The photos you said you sent did not make it to us but if the head shows any signs of damage, like being bent as you said, I recommend replacing any of the damaged parts as soon as possible. Using a system that has any parts that have been damaged will present an unsafe situation and should be avoided. Let me know...
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