MAN# 650102A
HLY-3401 3-
3/8” multi-gauge display
(weather and vibration resistant for exposed environments)
Operation:
The gauge needs only the red and black wires connected to light up. Connect the red wire to11-15 volt power and
connect the black wire to a main ground point.
The voltage gauge reads from the orange wire. This can be connected to the same power as the red wire or to a
different power location in the vehicle.
The purple wire should connect to the fuel level sender. The stock or existing fuel sender can be used with this
gauge.
The gray wire should connect to the supplied oil pressure sender. The sender uses its case for the ground
connection. The mounting threads are a tapered dry-seal type. Do not use any sealant on the threads.
The green wire should connect to the supplied water temperature sender. The sender threads are a tapered dry-
seal type. Do not use any sealant on the threads.
When the blue wire is switched to power, the display will dim for night viewing. This can be connected to a toggle
switch or left disconnected.
Typically this will connect to a ‘parking light’ circuit if used.
The white/red wire can be connected to an optional warning light. When any of the gauges go outside of their
operating limits the readout will flash and the white/red wire will provide a grounded output for indicators drawing
less than 250mA, see “Using external warning indicator” below for additional information.
The white/blue wire is only used for changing the gauge warning points and selecting the fuel sender type. The high
temperature, low pressure, and low voltage warning points are user adjustable. The factory default settings are
250F, 10psi, and 11.0 volts respectively.
The fuel gauge will display “FL” until the sender type is selected.
Using external warning indicators:
The white/red wire provides a ground trigger whenever the gauge is outside its set limits. Low current indicators
(less than 1/4 A) can be activated directly by connecting their power wire to 12 volts and connecting their ground wire to the
white/red output wire.
For higher current buzzers or lights, a relay will need to be used to switch the indicator on. Dakota Digital’s RLY-1
30A relay may be used for this. One of the relay coil wires should be connected to 12 volts and the other relay coil wire
connected to the white/red warning wire. When the gauge is outside its limits, the relay will turn on. The relay contact wires
can be used to switch the higher current.
