I have recently bought a 2014 Nissan NV200 Taxi model. I am not running a taxi service, but it has a custom nameplate on the roof light that I would like to be able to activate manually. There are other taxi-related components in place that function already, and are detailed in the owner's manual, but as far as I can tell the roof light and the "vacant" signs above the tail lights are only able to be controlled as part of the taxi service device hookup.

I have downloaded the NV200 Taxi Bodybuilder's Guide, which lays out all of the upfitting relevant components such as where to install the taxi service device, driver info panel, passenger info panel, and card reader devices. The taxi service device has a specific harness inside the dash, and all the other components listed connect to the service device. There is only one harness in the entire vehicle that is related to the upfitting taxi service components. The spec for that harness is as follows: Harness location and pinout

Terminal No.    Color    Signal Name  Gauge   Max Load
1               Red      IGN          20      20A
2               Green    BATT         20      20A
3               Violet   ILL          28      3A
4               White    8 Pulse      28      -
5               Black    GND          20      20A
6               Gray     TAXI +12V    28      250mA
7               Pink     TAXI GND     28      250mA
8               -        NOT USED     -       -

Given that this is the only point of connection to the vehicle's electrical for the taxi module, I think it's safe to assume that the control for the lights comes through here in some form. Also given that the vehicle is generally electrically the same as the base NV200 model (minus a couple extra wires to power the intercom and some light switches) I think it's safe to assume that the control is done as a simple switch, rather than a digital signal being sent to a taxi specific control module under the dash or hood.

So my prevailing theory is that the TAXI +12V and TAXI GND are the circuit for the lights, and that the +12V is not denoting power coming from the harness, but what should be sent through the harness. However, the math on that circuit works out to being a max of 3 Watts, which even with LEDs I feel is too low to power all three lights.

Given the niche market for this question it pretty much has to be two questions. Obviously if someone knows for sure how the wiring works, or a solid resource to find that answer that would be preferred. Otherwise, what would be the safest way of testing this harness using a standard voltmeter to put my theory to the test?

I know that if those pins are indeed the light circuit that it likely won't be as simple as installing a toggle switch and connecting the IGN to TAXI +12V and TAXI GND to GND, but I will deal with that when I get to that point.

  • 3 amps allows 36 watts, which is quite a lot even for incandescent bulbs. Remember that signage lighting does not need as much power as lighting for casting illumination on external objects. You have enough for say two 10-watt bulbs in a roof sign, and say 6 watts in the rear sign. LED lighting will consume rather less. For example, a flashlight can be seen from vastly further away than the range it will illuminate. Nov 6, 2020 at 20:52
  • @WeatherVane The 3A circuit is for ILL, which based on my experience with head units is tied to the headlight circuit and used for triggering dimming or dash illumination. The signage in question is meant to operate independently of the vehicle lights. It will not be tied to the ILL circuit.
    – Logarr
    Nov 6, 2020 at 20:58
  • Presumably the missing unit is a metering device and ILL means the 'illumination' which it controls. The 3A would apply to what the unit (if you had one) can supply. Nov 6, 2020 at 21:14
  • @WeatherVane Not to be argumentative, but in every case I have seen ILL used in a vehicle harness it provides power when the parking or headlights are powered. It is a lower amperage because it's only used for low wattage dash lights. Though that is an easy test to confirm.
    – Logarr
    Nov 6, 2020 at 21:29
  • I have no idea about US law, but check if a vehicle "impersonating" a licensed taxi in some way (e.g. with a light that could be misinterpreted by a member of the public as showing it is available for hire) is legal or not. For example in the UK licensed taxis may be allowed to use bus lanes that are not available to ordinary cars, not to mention different rules for legal parking.
    – alephzero
    Nov 7, 2020 at 23:58

1 Answer 1


While I don't know much about taxi devices specifically, I believe that your assumption is correct and TAXI +12V and TAXI GND are related to the illumination of the sign. The resistance between those two should be not less than 48 Ohm (judging from the .25A max current), however I believe that you'd be safe to apply 12V from a regulated power supply (set the current to the maximum of 0.25A) to it and see if the signs illuminate.

Like you said, it is also possible that those pins are power-only and the light unit contains its own microprocessor, which then receives the signal through the pulse wire to turn on and off. Again, as you said it is not so simple from that point on, you'll need to know the protocol used and have some sort of a microprocessor device to issue the commands.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .