16720-16721-InstructionSheet
Derale Performance, Los Angeles, CA
800.421.6288
www.derale.com
INSTALLATION INSTRUCTIONS
SINGLE STAGE ELECTRIC FAN THERMOSTAT
PART # 16720 & 16721
WIRING
Before starting, disconnect the Negative (-) cable on the vehicles battery.
Using the electrical connectors and wire ties provided, follow the directions below.
When extending wires always use the identical gauge wire as provided.
Using the Blue 5/16” Ring Terminal provided attach to the Positive (+) terminal of the battery.
Using the Blue #10 Ring Terminal and #10 Sheet Metal Screw provided attach to a good chassis ground (-).
Using the Blue Female Connector provided, attach the Yellow Wire to EITHER terminal on the Thermostat
Switch.
Using the Blue Female Connector, Blue Wire Tap Connector and Wire provided, attach the remaining
Thermostat Switch Lead to a Positive (+) switched ignition source.
Attaching this wire directly to a 12V non-switched source will allow the fan to run after the vehicle has been turned
off which could effect the vehicles battery performance.
The green wire is designed to work in two different configurations. When used, this will allow the fan(s) to
be turned on regardless of the temperature of the thermostat as it simply overrides all other functions. If you choose to not use
this option disregard the wire.
1.
A/C Override - Using the Blue Wire Tap provided, attach the green wire to the positive (+) lead on the air conditioning
compressor.
2.
Manual Switch Override - Attach the Green Wire to the manual switch NOT PROVIDED. (See Diagram #4 on page 2)
See page 2 for single or dual fan configurations.
WARNING:
See Diagrams # 2 & 3 on page 2
Red:
Black:
Yellow Wire -
Thermostat Switch -
Warning:
Green (Optional):
Orange/Blue Wires:
(Continues on reverse side)
Diagram #1
Please read these instructions completely before beginning installation
THERMOSTAT PROBE INSTALLATION
RELAY WIRE HARNESS MOUNTING
Placement:
generally
1/8” NPT port installation -
3/8” NPT port installation -
Locate a port on the vehicle,
found on the
vehicles radiator, manifold or water outlet.
Using Teflon Tape or suitable sealant
install the Thermostat Switch into the port on the vehicle.
Using Teflon Tape or suitable sealant
install the 3/8” x 1/8” NPT Reducer Bushing into the 3/8” NPT port on
the vehicle. Using Teflon Tape or suitable sealant install the Thermostat
Switch into the 3/8” x 1/8” NPT Reducer Bushing.
(See Diagram #1)
1.
Taking into consideration probe placement and wire routing
requirements, choose a convenient location.
Avoid mounting near HOT engine components.
2.
Using the relay bracket as a template, mark and drill a 5/32” hole in
the proper location.
3.
Using the #10 Sheet Metal Screws provided, install the relay/wire
harness.
3/8”
NPT
3/8”
NPT
1/8”
NPT
1/8”
NPT
1/8”
NPT
1/8”
NPT
KIT CONTENTS
QTY. DESCRIPTION
1
1/8” NPT Thermostat Switch
1
Relay Wire Harness
1
3/8” x 1/8” Reducer Bushing
3
#10 Sheet Metal Screw
4
4” Wire Ties
1
Roll Extra Wire
QTY. DESCRIPTION
1
Blue 5/16” Ring Terminal
2
Blue #10 Ring Terminal
2
Blue Butt Connectors
2
Blue Female Connectors
2
Blue Wire Tap Connectors
IMPORTANT
This single stage electric fan thermostat will control up
to two different fans with a
If fans exceed
25 amps combined we recommend using one switch
per fan.
COMBINED MAXIMUM
DRAW OF 25 CONTINUOUS AMPS.
TOOLS NEEDED
12V Test Light
Wire Stripper
Crimping Tool
”
5/8 Open End Wrench
11/16” Open End Wrench
Teflon Tape
Standard Screw Driver
or a 5/16” Nut Driver
Drill
5/32” Drill Bit
