Full-On 2004 GMC 2500 Diesel Truck Buildup, Part 1 - Build It!

Next up was the Amp Research Bed Step. Tools needed include: 3/16-inch Allen wrench, 8mm Allen wrench, 18mm deep socket, and a wrench with an extension. Have you or someone else ever stepped on your wheel while trying to get into the bed of the truck and broken the plastic cap? We have had that happen more than once. The Amp Research Bed Step is the best thing ever invented. We are used to climbing on our tires to get into the bed, and it's not smart. Amp Research states this is a 20-minute install but we found it can be installed in 10 minutes.

We located the bumper attachment point. Using an 18mm socket, we removed the two bolts on the bracket.

The step itself comes pre-assembled. Our truck is a GMC 2500HD so we will not be using the long-socket cap screws or the spacer provided.

Two short-socket cap screws were used to secure the Amp Research Bed Step mounting bracket onto the step linkage using an 8mm Allen wrench. They were torqued to 33 ft-lb. We found it easier if we visualized how the mounting bracket was secured to the bumper attachment point first.

We slid the Amp Research Bed Step mounting bracket over the factory studs and then re-installed the factory bolts and torqued them to 70 ft-lb.

Next, we installed the step pad assembly onto the linkage. With the linkage in the down position, we used the two socket cap screws provided. The instructions say to not tighten these socket cap screws yet. It is a good idea to press the step up and make sure the step is not hitting anything under the bumper. We also slid the step out and away from the hitch, so that our foot could grip it and press it down. Once we were comfortable with the placement, we torqued the two socket cap screws with a 3/16-inch Allen wrench to 10 ft-lb.

With the step in place, you will have no problem accessing the bed of your truck.

Amp Research Power Steps were next.. These steps are one of those things that you ask yourself, "Why didn't I get these sooner?" The Amp Research Power Step is easier to use than a tube step and is lower to the ground than most tube steps. A tube step takes up a lot of room and looks bulky next to the truck. With the Power Step, your truck will look clean and classy. This is a fairly complicated install. You should know your way around the toolbox before attempting this. Amp Research states this is 4 out of 4 on the skill level with a 3-hour install time. We had to remove our tube steps on our 2004 GMC 2500HD first.

We opened the box and made sure everything was there. The instructions contained a parts checklist.

We installed the supplied replacement brake cable guide in the forwardmost position on the framerail.

We used vise grips 1/16 inch ahead of the rearmost sill drain to clamp the template. With the template secured, we drilled a 1/8-inch starter hole. After the template was removed, we drilled the hole out to 2 1/64 inch. We clamped the template with vise grips to the pinch-weld 1/8 inch behind the forwardmost mounting tab then drilled. Before going any further, it was time to remove the sill plates from the cab, front and back. Then we moved all of the wires out of the way by pulling them to the side.

The distance between each hole was measured then drilled. This is done for the front and rear. We then used a straight edge and marked a line from the center to the underside of the cab. This is approximately a 5- to 7-inch line. We then centered the Amp Research Power Step upper support mount on that line. A 1/18-inch starter hole was drilled, then the support mount was removed and 3/16-inch holes were drilled. It is important to only drill through the first layer of sheet metal. We attached the Power Step upper support with the #14 sheet metal screws. The rear support was partially obstructed by the frame support, so only one sheet metal screw was needed.

The next step was to mount the Amp Research Power Step linkage assembly and upper bracket and loosely tighten it. On our '04 2500HD, the motorized linkage assembly went to the front and on the passenger side it mounted on the rear.

We then slid the step onto the linkage. The step has a sliding T-nut so it can be moved as needed. We aligned the end of the board with the rear edge of the back door and tightened it to 10 ft-lb. We then tightened all hardware on the Amp Research Power Step upper support and linkage assembly to 16 ft-lb.

The Amp Research Power Step controller was mounted to the factory wire conduit above the brake booster on the driver side of the truck with the provided cable ties. After plugging in the wire harness we made sure the tabs engaged.

Next, we removed the 30-amp fuse in the red Amp Research Power Step power cord. We attached the power cord to the positive battery lead in the junction box and attached the black ground to the stock box-mounting bracket labeled "ground". We routed the long wire above the engine and down the passenger side wheelwell and zip-tied the harness in safe locations. The short end was routed down the driver side. Route the wires along the framerails to the steps and secure with zip ties.

A hole was poked with a Phillips screwdriver through the rubber grommet. The carpet and padding have to be lifted, but not removed. Both wires were pushed through the hole.

On the driver side we carefully removed the wire wrap and found the light blue with the black stripe, while the green wire with the black stripe was on the passenger side. Using the supplied Amp Research Power Step Posi-Taps, we spliced the shorter trigger wire into the wire found in the previous step. Next, we removed the front driver and passenger side door panels.

We pulled the tab at the top of each speaker and let the speaker hang down. Then we threaded plastic tubing through the accordion, as this made it much easier to get the flimsy wires through. You can try to get the wires through without the plastic tube, but it will not be as easy. After feeding the wire through the plastic tube, we pulled the tube out from the door side. Using the Posi-Taps, we spliced the trigger wire into the door-ajar wire (the driver side is gray with a black stripe, and the passenger side is black with a white stripe). We secured all wires with electrical tape and zip ties.

It's important to make sure all of the harnesses are plugged in and secure on the door panels. If they are not, the connection is not complete and the steps will not work. Also, we checked to make sure the power door locks and power windows still worked. If these accessories work and the steps do not, then the wiring may be incorrect. We loosely hung the door panels so we could close the doors and test the steps. Next, we replaced the Amp Research Power Step 30-amp fuse in the red power line. After that we checked to make sure the steps worked, and were even.

We thought it was extremely important to install an Optima battery since we planned to have a lot of electrical equipment on the truck. Before purchasing our '04 GMC Sierra 2500 HD Duramax, we tested the voltage on the batteries. We knew both batteries would need to be replaced as soon as possible. When we think of a "great" battery, we think about Optima. We have only used Optima in our project trucks and personal vehicles. Obviously before you can install your new Optima Yellow Top batteries you will have to remove your old batteries. Remember to remove the black ground connection first, and the red connection last.

When installing new Optima Yellow Top batteries you should install the red connection first, then the black ground connection last. A new Optima adaptor was needed to hold down the battery. The lip on the new Optima Yellow Top was slightly different than a stock battery. The stock hardware worked fine. It was that easy. We will have years of good performance and no worries with our Optima batteries.