Expert Answers about GMC

• Running Light Circuit Not Working on 4- to 7-Way Adapter # 37185
• On the Hopkins 4- to 7-Way adapter # 37185 the brown wire is the running light circuit. There could be a break or a problem with the connection on that brown wire somewhere between its 4-Way and the back of the 7-Way. Also make sure that the white ground wire on the adapter is attached to a clean and corrosion free bare metal surface. This wire must have a good connection or you could run into problems with some of the lights. A weak ground could be the result of this issue since the running...
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• BK LED on Curt 7-Way Adapter, Part # C57674, Remains Lit Even Without a Trailer Connected
• If you do not have a proportional brake controller (but instead have a time-delay type) the LED being lit could indicate a short to the controller output circuit. In some cases the manual brake switch on your controller may be partly engaged; this would also cause a signal to be sent to the 7-way BK LED. You can correct this by flipping the manual switch on and off several times to clean the contacts. If you are using a proportional type brake controller such as the Prodigy P2, part #...
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• Can Base of Andersen Ultimate 5th Wheel Hitch Turned Around
• Yes, the base of the Andersen Ultimate Connection like our 5th wheel base rail version # AM3200 (I'm assuming you have the gooseneck model which we don't have available) can be reversed so that the offset is turned towards the cab instead. This will place the camper's pin weight more over the rear axle which is going to result in a smoother ride and better support during travel. Since your Sierra has the 8 foot bed cab clearance isn't a concern so there's no problem with doing this.
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• Where Is The Trailer Running Lights Fuse On a 2014 GMC Sierra 1500
• For starters, the Curt TriFlex Trailer Brake Controller part # C24VV and Curt Custom Wiring Adapter for Trailer Brake Controllers part # C51451 have nothing to do with the running light circuit. The most likely cause of this issue is a blown fuse on the vehicle. For your 2014 GMC Sierra 1500, the running light fuse is in the #15 position on the fuse box which is labeled as "Trailer Park Lamps".
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• P3 Brake Controller Never Says NC and Will Not Go to Sleep in a 2009 GMC Sierra
• The P3 brake controller # 90195 might be sensing that there is power draw. The usual cause of this is a dirty or corroded trailer connector. Make sure that the connector is clean and free of corrosion inside where the wires attach and outside on the pins. This could also be the reason the controller is not going to sleep. If there is power draw caused by corrosion, then the controller may think that the brakes are being applied and it will not go to sleep. You will also want to make...
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• Troubleshooting Brake Controller Only Sending 12V Power with Manual Override
• From what you stated it sounds like you have a proportional brake controller like the Tekonsha Primus IQ # TK90160. This kind of operation is normal for a proportional controller because they have an internal inertia sensor that helps to determine how much power needs to be sent back when you are coming to a stop. If you are testing all of this while sitting still then the inertia sensor can tell that the vehicle/trailer isn't moving and so no power is needed for the brakes. The manual...
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• Troubleshooting Running Lights Come On Then Shut Off On Trailer
• It sounds like you either have a weak/bad ground or your lights are drawing too much power. In order to find the problem lets start by double checking the connector on your 2020 GMC Sierra 2500. Using a circuit tester like # PTW2993, check for power on the running light circuit. More than likely you have constant power here and the issue is on the trailer side. If it is on the trailer side I would start by inspecting the connector. Make sure it is free from debris and corrosion. From...
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• Troubleshooting Turn Signal Circuit of 7-Way Not Functioning on GMC Sierra
• First thing I'd recommend trying is cleaning all of the pins on your 7-way. This problem is almost always caused by corrosion or dirt build up on the pins of the connector which prevents the circuit from functioning. Next thing you can try is checking the fuses under the hood of the truck. I also attached a help article on trailer wiring troubleshooting for you to check out as well.
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• Troubleshooting a Sticking Handle On a Reese 16k 5th Wheel Hitch
• The 16K Fifth Wheel Hitch by Reese, item # 30047, has a groove in the handle that a latch rotates into. If the latch is not rotated toward the rear of the truck then the handle will not move and hitching should not be possible. If the latch was not rotated and hitching was attempted then some of the handle parts could have been bent. During normal hitching you should not move the handle out. You should back the truck slowly into the trailer and allow the hitch to move the handle out. Once...
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• Blue Ox Alpha Tow Bar # BX7365 Makes Popping Noise when Towing with Pickup Truck
• The first thing that you will want to check is to make sure that the Blue Ox Alpha Tow Bar # BX7380 isn't binding. This could be the case if your tow bar is not completely level. When towing with a motorhome you have a 3" safe zone (see attached picture), but that is not the case when using your pickup. To remedy this you can use a High-Low adapter. I have attached our selection of adapters as well as a helpful article to help you decide if you need one or not. I also spoke with my contact...
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• Troubleshooting a Pilot 2-6 Brake Electronic Brake Controller for not Detecting Trailer
• You may try attaching your vehicle to your hitch and see if that helps the problem. Some trailers do ground through the hitch ball to the tow vehicle. According to the install instructions for the Pilot Brake Controller # 80550 the following things are probable causes to what you described. Poor connection on BRAKE line (BLUE wire). Power set too low. BLACK & WHITE wires reversed, controller destroyed. Open on GROUND line (WHITE wire) I attached a set of instructions for this brake...
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• Can an Electric Brake Controller Output Go Higher than its Maximum Setting
• When a controller is set to its maximum output it will send back 12 volts of power to the trailer brakes. If this is not adequate then it could be an indication that the full power is not reaching the trailer brakes or that the brakes need to be adjusted. It could also mean that there is something wrong with the brake magnets. But there is no way to go beyond the maximum output. To test the output you will need a multi-meter like # PT89ZR if you do not already have one. At the maximum...
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• Testing an Electric Trailer Brake Controller
• The ground may be sufficient but it wouldn't hurt to test it using an alternate ground location as well. Perform the test using just the manual override and not the brake pedal. Make sure the controller is set to the maximum output level and that it is mounted within the range specified by the instructions. Also make sure that it is not tilted or turned to the side. If the controller you are using has a leveler knob, you will need to make sure it is properly adjusted according to the...
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• Troubleshooting Curt T-Connector On 2018 GMC Terrain Not Having Left Turn Signal/Brake Light
• That is a pretty weird issue! I would start by checking that the connector for the Curt T-Connector Wiring Harness # C56375 you installed in your 2018 GMC Terrain is fully seated into the factory connector. If that is the case then go ahead and remove the connector and check both the Curt and Factory connectors for any debris or corrosion that may have worked its way in there causing your issue. Next go ahead and check that the two relays in the fuse box of the rear cargo area are completely...
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• Constant Power On Brake Controller Without Brake Pedal Depressed
• I suspect that you have an internal error on your brake controller or a wiring issue. In order to test for an internal error you will want to sever the brake output wire from behind the controller and test for power. If there is power on this wire without the brake pedal depressed or the manual override applied then there is an internal error and it will need to be replaced. In regards to the stop light switch wire, there should only be power here when the brake pedal is depressed. If...
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• Are Replacement Rod And Nuts Available For A 2001 Circle J Riata Horse Trailer Front Jack
• The only rod and nut replacement we currently offer, part # TJD-12000-RODNUT, is a bit smaller than the one you have so the only option that we can offer would be a complete replacement of the jack. You'd want to check the GVWR of the trailer and choose a jack that's rated for at least 20% of the GVWR. For example, the Buyers Products Heavy-Duty 4" Square Jack w/Front Pin Drop Leg # 3370091415H can handle 12,000lbs and has 26" of lift capacity. It has a weld-on installation and comes...
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• Troubleshooting An Air Lift WirelessONE Compressor Remote That Wont Pair
• The Air Lift WirelessONE Compressor System for Air Helper Springs # AL25980 has an optional ignition source connection makes the compressor "sleep" while the ignition is off to prevent battery drain so you most likely just need to place the ignition in the on position to wake up the compressor and then try pairing your remote.
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• Metal to Metal Noise While Towing a 5th Wheel Trailer Coming from the Jaws of the 5th Wheel Hitch
• If this noise occurs during starts and stops or any time there may be back and forth movement of the trailer then it is normal to get some metal to metal contact as the trailer king pin bumps around in the jaws of the hitch. The double jaw design of the Reese 5th wheel hitch, # RP30051, is secure but it is not so tight that it will eliminate all movement. You also want to make sure the trailer is not high hitched. This means that the king pin is not fully seated in the hitch. When hooking...
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• Diagnosing a N.C and C Code for a P2 Brake Controller on a 2007 GMC Sierra
• It sounds like somehow your Tekonsha Prodigy P2 Brake Controller # 90885 got put into electric over hydraulic mode based on the codes you are seeing. To change over to regular electric brake mode you will need to start by pressing the Boost Button for 5 seconds while the brake pedal is pressed until (.r) displayed. While continuing to have the brake pedal pressed, momentarily release the Boost Button for less than one second and then press and continue to hold the boost button down for...
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• Troubleshooting Right Side Trailer Running Lights Not Working With 2016 GMC Sierra 1500
• If you haven't already checked the ground connections I would go ahead and start there. Between the running lights not working and the other lights being dim that is a good bet. Make sure they are secure on a clean, bare-metal surface. If that is not the issue we can start some testing. Using a circuit tester like the # PTW2993, check the connection at the rear of the truck for power. If you have power here, check the trailer connector and the wiring again. If you don't have power then...
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