What a day! The bite is hot, and the fish have hit like gangbusters for the last two hours. It's now early evening, though, and it's time to head for the ramp. One last cast. One more hook-up. You settle into the cockpit and hit the down button on your custom foot-mount­ed trim controls. Nothing. The engine stays trimmed up. You hit the trim switch on the throttle. Still zip. Top it off your chart plotter won't work, either. Now what? Under the dash you go, flashlight in hand only to find a rat's nest of wires. Most of today's boat builders make above-average products in almost every way-until it comes to wiring. If your boat is typical, under-dash wiring leaves a lot to be desired , especially when a little trou­bleshooting is necessary. All those wires crammed into such a small area make it tough to figure out where the problem is. That's why tracing a short in the average bass boat often turns into a nightmare for boat owners. That nightmare is easily cured, however. Here are some hints and tips to help you learn which wire does what, how to trace circuits according to code, and how to dean up that rat's nest under the dash and at the transom.


Ideally, every bass and walleye boat would have a clean, easy-to-read wiring diagram posted in a conspicuous place under the dash or rear hatch so problems are traceable. Unfortunately, most don't. One bass boat builder, Charger Boats in (Richland, Missouri), has seen the need, and all of its models feature an excellent wiring schematic laminated to the under­ side of the rear hatch. If there's no factory wiring schematic for your boat, it's a good idea to take an after­noon or evening to create your own rudi­mentary diagram. It's pretty simple and requires only a few tools and some basic knowledge of boat wiring codes (see chart below for wire color codes). A good ohmmeter, a test light with a sharp probe, a couple of jumper leads (use a 20- foot length of 14-gauge wire with alligator dip on both ends), label tape, a notepad and a pencil are all that's needed to create your own wiring schematic. Not only can you identify each circuit and its purpose, you've also gained confi­dence for an emergency or other trou­ble shooting session because you know your rig's system firsthand. What's more, because most of today's boats use basically the same wiring systems and color codes, you can help your boat-owning buddies if they encounter problems on their rig.



Begin by crawling under the dash with a trouble light. (It might help to remove the seats, foot throttle, etc so you can get comfortable.) Start by labeling the backs of all of the gauges and switches with a black permanent marker. Use labels if the marker doesn't show up. Once completed, each gauge and switch will be instant­ly identifiable under the dash. Next, take one gauge at a time and note on a pad of paper the color of each wire attached to it. Most gauges have the same wire-coded circuits: lighting (blue), ground (black), positive (purple) and a sender of some other color. Some, like the speedometer and water pressure gauges, also have a tiny rubber hose for water feed. You can label each sender wire at the gauge connection, then follow it down the side of the boat to the transom area or engine and label it there as well. If you're not sure of a wire's function, turn the power off, then test it at both ends with an ohmmeter. Connect the test lead to one end of the wire, then to the ohmmeter. Connect the other ohmmeter lead to the other end of the wire. If the wire is continuous, the meter will show a zero or very low reading. This indicates the wire is complete from one end of the boat to the other, with no breaks or shorts to ground. This is a handy test in a number of instances. If there are several wires that are the same color (for example, if your boat has two water-temperature gauges, both with tan sender leads), the ohmme­ter can be used to tell which one goes to which gauge. Be sure to label them once you know for sure. If your boat is wired improperly with the wrong color wires (for example, using red instead of purple for the switched positive Ieads;), you can identify which wires are used for each function by using the ohmmeter. A test light is also handy for this pur­pose. Suppose your boat was wired using red wire for every lead that's positive. While red is a common hot wire color, purple is the proper color for wires that become hot when the key is switched to the "on" position. To test which ones are hot and when, simply probe each suspect wire with the test light as the key switch is turned on and off. If the test light glows no matter what the key position, that wire is hot all the time. This is also an excellent time to check all the ground circuits. These wires should all be black. Use the ohmmeter to check for continuity between every ground wire and the battery and/or engine ground. If your rig was poorly wired, you might choose to replace each wire, one by one with one of the correct color. This is really the best way, but it can get expensive and time-consuming. Labeling each wire is far cheaper and easier. Be sure to use labels that won't fade or wash off; tech-heads and gadget lovers will want to check out Brother's P-Touch electronic label maker, which is available at computer and office supply stores. It can be loaded with clear or colored water­ proof label tape and makes truly profes­sional labels. Finally, if it's difficult to identify the ter­minal connections on the back of each gauge, look closely with a bright light. Most gauges have embossed letters next to each terminal stud indicating the cor­rect connection. Usually, abbreviations are used to indicate stud function. like "GND" for ground, "SE" for sender and "POS" for positive.



Wire routing is a sore point with many professional riggers. Too often, the assembly folks at the factory, with little thought as to how the wires should be strung and supported throughout the boat, leave the dealer's boat rigger (and the customer) with a snarled mess to unravel. This happens because the instrument panel is pre-wired at an assembly station, just like a radio or television is at large factories. Next, the panel is installed into the boat while the deck is still upside down and loose from the hull. When the deck cap and hull are finally assembled, wires may get pulled tight in some areas and left dangling in others. In addition, wires may get twisted into knots instead of running straight to each gauge or switch because far too few wire support clamps are used through­ out the boat. All of these problems can be corrected after the fact; it just takes a little patience. Again, start behind the dashboard. It may be necessary to disconnect a few wires in order to untangle them and or create a more direct path to each gauge or switch. This underscores the need to label each wire before beginning this operation. As each wire is re-routed, try to create an orderly pattern. For example route all wires and hoses along a single central path and break off from that path in group of two, three or four wire to reach several gauges at once. Use small tie-straps to bundle these wires together before they reach their destination. As the wires are disconnected and then reattached, pull on each connector to make sure they're not loose or dan­gling by one wire strand. If they are, use a new terminal connector before reattaching the wire. This is also a good time to clean up any corroded terminals or connectors. Most are made of brass, which cleans up easily with a few strokes from a stiff bristled brush. When crimping new ring terminal or butt connectors I try to use the kind without any plastic insulation. If these aren't available, pliers can be used to hold each connector while the plastic is stripped off with a utility knife. This allows for a more thorough and positive crimp joint. The best insulation is heat-shrink tube because it's more flexible than plastic sheathing and, therefore , acts as a strain relief for the wire as it bends to meet it's connection. Heat-shrink tubing is available at most auto parts stores and is easily installed using a simple butane camp stove lighter. It costs about $3 at RV and camping supply stores. Be sure to slip the tubing over the wire before installing the terminal, though-it won't fit over it afterwards. Cut each piece long enough to cover the bare metal of the terminal and allow it to extend down the wire about 1 inch from the end. By the way, if you don't have a local source for electrical wiring products and supplies, contact Wrangler Power Products (800/999-2616) in Prescott, Arizona. Wrangler offers a catalog filled with everything needed to rewire a boat or tow vehicle! Once the dash panel is cleaned up, support the main wire bundle every 6 to 8 inches using rubber-coated wire clamps. These are available separately in many sizes for different wire-bundle diameters or in kit form with all sizes included. The kit form is recommended because each size comes in handy depending on the job performed. Select the proper size; too large will allow the bundle to move and snag, while too small may pinch a wire or collapse a hose. Attach these clamps to the backside of the dash with small self-tapping screws. If the clamps are plastic, be sure to use a flat washer under the screw head so the soft clamp doesn't distort when it is secured. As a final touch, cover the main wire bundle with a short piece of split-loom. This stuff is excellent because it provides for a neat and tidy wire cover, yet it still allows the wires to emerge at their proper loca­tions since they pass through the split in the loom. Split-loom installs over an existing bundle without the need to disconnect any wires. Be sure to allow for any needed lack, especial­ly around tight comers.




As the wire bundle is run down the side of the boat under the gunwale, secure it with more cable clamps. Often, the builder has glassed in a fiberglass loop for the steering cable to run through. These make excellent wire supports, but the cable will have to be tie-strapped together so they won't sag or become tangled over time. Try to get the wires to run straight because they're strapped together; don't let them curl and cross over each other. Watch carefully for kinks and, again, be sure wires and hoses aren't stretched too tightly when they're strapped down. As the bundle makes its last turn around the rear and heads toward the transom area, it should have a radius of at least 4 inches. The throttle and shift cable usu­ally end up bundled in with the rest of the wires; check to make sure they aren't kinked. The transom area can get as messy as under the dash. Fortunately, there are usu­ally not a many wires. It helps to separate the wires into three groups as they come out from under the gunwale. First one group will go to the batteries. Another group will go to the engine and enter the engine cover on the port side. The third group will also go to the engine but enter on the starboard side. Usually the electrical wire , water­ pressure hoses and temperature-gauge senders enter the engine on the starboard side, while the fuel line, oil line,shift and throttle cables, and power trim harness enter on the port side. Group these wires, cables and hoses together as neatly as possible and tie-strap them into bundles. The group that goes to the batteries will split again, this time into positive and negative cable bundles. Tie-strap these together, making sure they have a clean route to me cranking and auxiliary batter­ies. Any fuseholders should be labeled and easily accessible. Mark all positive wire with a band of red tape so that it's impossible to hook them up incorrectly after winter stor­age, etc. If there are too many wires going to each battery terminal , invest in an accessory terminal extender (avail­ableable through Bass Pro hops, Cabela 's and other catalogs). These units attach to the battery lug and provide connec­tions for multiple wires , without mak­ing a maze of haphazard wire junc­tions. Coat all connections liberally with dielectric grease.



If your rig has a lot of exposed wire between the transom and engine, you may want to dress things up a bit with wire coverings. These can be a, simple as using Nylabraid flexible-weave hose and wire covering available at speed shops. This covering is attractive and inexpensive; it can be ordered in a myriad of col­ors and typically costs less than $20 to do an entire boat. Outboard hose dress-up kits are a bit more involved but look neater. These are usually rigid-wall flexible hoses ( similar to pool vacuum hoses) that cover wires and hoses and attach to the boat's deck with anodized aluminum fittings since these require cutting extra holes in me deck, be sure they're what you want before installation .Typical costs average $60 to $90. Whichever method is used, be absolute­ly sure that the wires and hoses going to the engine cannot kink or pull tightly as the engine is turned, tilted or jacked. When all is done, your boat will look a lot tidier-and you will know exactly where to look should any problems arise.

John Tiger Jr

Leave a comment