Navigation Lamp Circuits Used on Newer Boston Whaler Boats

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Navigation Lamp Circuits Used on Newer Boston Whaler Boats

Postby jimh » Tue Jan 01, 2019 12:54 pm

This article will explain some details as seen in the the wiring diagrams used by Boston Whaler, particularly in regard to the switch controlling the navigation lighting.


Let's look at the form of electrical diagram used by Boston Whaler. Fig. 1 (below) is excerpt from a typical Boston Whaler drawing, to which I have added some annotation.

Fig. 1. Excerpt from a typical Boston Whaler electrical diagram.
bostonWhalerElectricalDwg.png (13.61 KiB) Viewed 140 times

Electrical wiring diagrams are usually laid out to be followed from left to right. In the above diagram the positive circuit is shown by the curved wire lines that connect to a current protection device, either a circuit breaker or a fuse, which I note as F1 (my added reference designator). The use of a curving line is likely meant to suggest that the actual wiring is a looping or jumpering from one component to the next. This wiring is described elsewhere in the drawing as being on a 12-AWG conductor with RED insulation that originates at the FUSE BLOCK. This conductor brings the boat battery positive to F1. F1 is a 3-Ampere device. From the nature of the symbol I infer it is a fuse. The fused output then connects to terminal 6 on switch S1. A note on the drawing indicates the conductor should be 14-AWG; the inference is this wire will also have red insulation.

Switch S1 is for control of the "NAV/ANC LIGHTS", as inferred from the legend on the drawing.

Also at S1 is the battery negative circuit, which I have identified as "Lamp Ground." This conductor is at the switch to provide for a return circuit for the internal switch illumination. It does not carry any of the current from the loads (other lamps) that are controlled by the switch. Elsewhere in the drawing this conductor is shown to be a 12-AWG black conductor fed from the "FWD GROUND BUS," which is a terminal bus near the helm dash panel where the switch is located. This terminal bus is shown to be connected to the MAIN GROUND BUS, detailed on another page of the drawing.

Coming from switch S1 are three conductors. These are identified with a three-part notation: wire number, wire gauge, wire insulation color. A wire associated with the "RUNNING LIGHTS" is identified as "203-16 GY." This is a 16-AWG conductor with gray insulation and should be marked in some manner with the number "203." This conductor goes to terminal "H" of a multi-pin plug P1. P1 mates with a multi-socket jack, J1. Wire 203 continues from J1 to its load, a lamp circuit noted as "RUNNING LIGHTS." From the lamp a second conductor, 204-16 BK continues to the FWD NEGATIVE BUS. This is a 16-AWG conductor with black insulation marked with the number "204." This completes the circuit for the lamp. In a similar manner, 207-16 BU (blue, the color used for instrument illumination circuits) is routed to the compass illumination. This means the compass illumination circuit will be powered whenever the sidelights are powered.

The wire marked 205-16 GY/WH (gray-white) is routed to the "ALL ROUND LIGHT." Note that the circuit for the ALL ROUND LIGHT, after passing through the connectors, is split, with wire 515-14 OR/WH (orange-white) spliced into the circuit. (In this drawing style, lines representing conductors that cross at right angles are not connections, but this line terminating into another line represents a joining of the circuit. In some other wiring diagrams, Boston Whaler uses a small dot to indicate that conductors are joined together.) The conductor insulation color orange-white is a bit of an oddball color, and in this case it goes to an optional entertainment device; the function is not described.

The wire insulation colors are generally abbreviated with two letters. The usual functions for the circuits associated with these insulation colors is also given in the table below:
BK =Black; grounds
BN = Brown; pumps
RD = Red; battery feeds
OR = Orange; accessories
YL = Yellow; blowers
GN = Green; bonding
BU = Blue; instrument lighting or general lighting
VT = Violet; engine ignition
GY = Gray; navigation lighting
WH = White; general alarms

In a separate article, the wire insulation color codes are broken down in much greater detail regarding what function they are used for.


The internal wiring of S1 is not detailed on the drawing seen in Figure 1. To understand the switch action you must get the details of the switch and terminals from the manufacturer of the switch. The Boston Whaler drawing does not specify the switch manufacturer or model. Without this information it will be almost impossible to know exactly how the switch operates, however, a drawing for another boat Boston Whaler does show the details of the switch action for the navigation lighting circuit. I will assume that switch is similar to the switch S1 shown in Fig. 1. Below Fig. 2 shows the switch action in detail from a segment of a Boston Whaler drawing; again, I have added annotation to show the insulation color, the wire gauge of the conductor, and the name of the circuit involved.

Fig. 2. Detail of switch wiring used by Boston Whaler to control navigation lighting.
bostonWhalerSwitchDetail.png (5.94 KiB) Viewed 127 times

The wiring of this switch is a bit unorthodox, so I will explain it in detail. The switch action has three positions. As the switch is drawn in Figure 2, the switch is in the first position, usually labeled OFF. Power comes to the switch at terminal 6, via a 16-AWG red conductor via a current protection device, either a fuse or a circuit breaker. With the switch in this position, no power flows to any load, and thus all circuits are off.

When the switch is moved to the second position, which will be labeled ANCHOR, power flows from terminal 6 to terminal 5 via the switch action, thence via an internal circuit inside the switch itself to terminal 2, and by the switch action to terminal 1. An external jumper connects terminals 2 and 8. Inside the switch the internal lamp is wired between terminal 7 and 8, so the switch indicator lamp illuminates, giving an indication that there is power applied to the load. The LAMP GROUND circuit at terminal 7 runs back to the nearby negative bus. Also connected to terminal 8 is the WHITE ALL-ROUND lamp circuit, so that lamp illuminates. This creates the proper lighting for an at-anchor indication.

When the switch is moved to the third position, usually labeled RUNNING but more properly "Underway", power is still flowing via terminal 6 to terminal 5, so the WHITE ALL ROUND circuit remains powered. Now power flows from terminal 2 to terminal 3 via the switch action, and power is present on terminal 3. Connected to terminal 3 are the SIDELIGHT LAMP circuit (the gray 14-AWG wire) and the COMPASS ILLUMINATION circuit (the blue 16-AWG wire). Both the sidelight and white all-round lamps are illuminated, creating the proper lights for an underway under command situation. The compass is also now illuminated.

The switch used is very likely made by CARLING and is part of their CONTURA series. Electrical switches are very highly customizable and can have thousands of combinations of switch actions, terminals, illumination, and other elements. I suspect that the switch used by Boston Whaler may be either a very odd combination of standard options or a customized configuration made specifically for Boston Whaler. (Because the switch appears to have an internal connection between terminals, I suspect it is a custom order switch.) In either case, finding a replacement switch sitting in stock at a general electronics distributor is probably unlikely.

If a replacement switch is needed, I recommend taking careful notes and a good close-up picture of the wiring for the present switch before removing the wiring from the switch terminals. The configuration of this switch is very non-intuitive. I recommend getting an OEM replacement switch from a Boston Whaler dealer, in order to be certain to get an exact replacement of this unusual switch.


As shown in Figure 1 the contact genders at the two connectors, P1 and J1, are arranged so that the source of power for most loads is provided on an male contact. This is generally not a good practice. Sources of power in connectors usually are on recessed female contacts (sockets) so that inadvertent contact with those sources will be unlikely and won't result in power being shorted to ground. However, in this particular example the power in that connector runs in both directions. Another circuit (not shown in the excerpt) carries through that connector the 12-Volt battery positive on a 12-AWG conductor coming from the FUSE BLOCK, from where it is fed power from a 6-AWG conductor that is on the load side of a 25-Ampere circuit breaker. Thus once the connector is unmated, there will be no power at all on the P1 side, since all the power ultimately is coming from the J1 aide. Therefore it is more proper to put the female gender contacts on J1 side.