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Painless Wiring Accessory Fuse Block Install On 2000 F250
by Lawrence Tognetti

This article is primarily meant to document the installation of a Painless Wiring (PW) accessory fuse block on a 2000 F250. The descriptions here are meant to serve as a guide to help you plan and execute your own installation. Therefore it is advised that the complete article be read and used as a guide to formulate your own installation procedure. The cost for this project was $45 for the PW unit and ~ $5-$10 for miscellaneous hardware.

Description & Purchasing the Painless Wiring 

Figure 1: Painless Wiring Fuse Box 70107

The Painless Wiring accessory fuse box (70107) provides 3 full time 12 volt fused accessory circuits and four fused switched circuits that are turned on by a relay. (see Figure 1) Most applications use an “ignition hot” wire to switch the relay, but if you are using it for other applications, such as switching on lights or accessories, any switched 12 volt source can be used. Essentially the PW unit connects to the battery, ground, and the switched signal source. Within the PW unit the 12 volts is wired directly to the 3 constant circuits (through 3 fuses) as well as to a relay that completes the path to the 4 switched circuits (through 4 fuses).

A good source for ordering the painless wiring accessory circuit is Geno's garage ( http://www.genosgarage.com ). Not only are they a pleasure to work with, they include their version of directions for your application. The author of this article deviated from these directions, but will periodically reference them in the installation description.

Figure 2: Trimmed Wires & Ground Strap

In its factory condition, the Painless unit has excessive wire leads for all of the accessory circuits (see Figure 1). To limit the amount of wire stored under the dash, all the wires were shortened and the bare ends of the individual accessory circuits were sealed with heat shrink tubing that can be purchased at any electrical or hardware store. The ends for the ignition hot "trigger" and the "battery" wires were left bare because they will be immediately used. Lastly, a ground strap was fabricated using black wire and the appropriately sized crimp ring terminals. Though probably not necessary, this was done because the quality of ground at the mounting location was not known and a grounding terminal was readily available under the dash. These modifications can be viewed in Figure 2.

Picking location to mount

Figure 3

The next step is to identify a mounting location under the dash. Ford Superduties have a natural mounting spot on the center of the cross bar at the bottom of the fuse panel access opening; there are even predrilled holes for mounting (see figure 3). With a mounting location identified it is necessary to determine a location for passing the wire through the firewall. On automatic trucks the plug blocking the clutch master cylinder-mounting hole can be drilled, but manual trucks require another solution. Please refer to the Geno's directions for using the clutch master cylinder-mounting hole.

Figure 4

For manual trucks the hole directly above the accelerator pedal can be used. This hole is stamped into the body for routing the accelerator cable in trucks equipped with gasoline engines. Since the fly by wire diesels don't use an accelerator cable, Ford plugs the hole. This hole can be viewed from under the dash in Figure 3. To use this hole, the plug first must be removed. Though the accelerator pedal and air intake tube from the air filter do not necessarily need to be removed, they were to ease access. From under the hood remove the right most retainer clips from the firewall shield. (see figure 4) These clips screw off and press back on. From under the dash press the plug with a blunt object, such as the extension of a 3/8 ratchet, until it pops out. When the plug pops completely out it will probably be pinched against the firewall by the shield. From under the hood gently pull the shield away from the firewall and the plug should drop to the ground. Go ahead and reinsert the shield's retaining clips. Take a punch and puncture through the shield from under the dash. The shield is just foiled cardboard so it should not take much effort. Once a hole is started take drill bits and manually enlarge the hole until you reach a maximum size of 1/2 inch in diameter. Now that the hole is complete, take a section of 3/8 wire loom (purchased at any auto parts, electrical, or hardware store) and push it through the hole from the engine compartment side and trim to length. The new wire loom will protect wires from rubbing on the edge of the sheet metal. A picture of the hole with the loom and wire can be viewed in figure 5 and 6.

Figure 5

Figure 6

Mounting & Wiring

The first component that must be mounted is the PW circuit breaker. This can be installed next to the starting solenoid / terminal block on the passenger fender using the supplied self-tapping screws. It should be noted that it is recommended to leave the breaker disconnected from the battery until all the wiring is completed. A picture of the mounted breaker and wiring can be viewed in Figure 7. Once the 10 gauge red wire is routed from the breaker, through the factory firewall wire loom, and through the firewall to under the dash, the work under the hood is complete for now.

Figure 7

There are two options for connecting to an ignition switched wire. The first is to T-tap into the red with yellow trace wire in the factory four wire harness at the steering column. Directions for using this wire are clearly illustrated in the Geno's supplemental directions. The second alternative is to use the switched wire supplied for PTO applications. This is a light blue with pink trace wire located in the center of the instrument panel, labeled “Power Take-Off Circuit”. It is taped to the generic toolscan connector, and blunt-cut with shrink wrap tubing over the cut ends. This wire was connected to the Painless pink wire with insulated crimp spade connectors. The battery connection was completed with a posi-lock connectors purchased at Napa auto parts. These non-permanent connections allow for easy removal of the unit without having to cut any wires.

Given that one hole on the factory cross bar was correctly sized and the other was much larger, a small 1/8 inch spacer was made out of some random bar stock that can be purchased from any hardware store. This will be mounted in between the PW unit and the cross bar, creating a solid bearing surface for mounting. In addition, two 10-24 machine screws, nuts, and locking washers were purchased to clamp the unit down. One additional oversized washer was used with the right side nut to accommodate the large. See figure 8 for the final mounting illustration. Though not much excess wire was present because most of it was previously trimmed, what was left over was placed neatly under the dash.

Figure 8

Barring any problems, once the final wire from the PW breaker is connected to the starting solenoid / terminal block, installation should be complete. It is recommended that a voltmeter be used to test that the PW unit is operating properly. Now all that is left is to buy and install accessories to power with the new PW fuse block.