Bill of Materials
Quantity
Wire
Harness 1
Relay
1
Thermostat
Switch
1
Brass
Probe
1
Retaining
Clip 1
Foam
Pad
1
# 14 Metal Screw
1
Blue Ring Connector
1
Blue Butt Connector
3
Scotch-loc Connector
1
16738 Single Stage Electric Fan Thermostat
Installation Instructions
Thank you for buying a Derale electric fan thermostat.
Please read these instructions completely before starting the installation.
The single stage electric fan thermostat will
control up to two electric fans with a
maximum amperage draw of 25 continuous
amps. This unit includes a 30-amp relay,
wiring harness and an air-conditioning
override circuit to activate the fan whenever
the AC is on. On vehicles without AC, this
lead can be used as a manual override. See
wiring instructions below.
Relay/Wire Harness Installation
1. Mount the relay/wire harness in a
convenient location, taking into account
the probe placement and wire routing, be
sure to avoid any hot components.
2. Drill one 3/16” hole and use supplied #14
metal screw to mount relay/wire harness.
Thermostat Probe Installation
1. Thread brass probe on to thermostat
switch
2. Insert the probe/switch between the fins
of the radiator core, as close to the water
inlet as possible. Keep pushing the probe
through the radiator core until it is flush
against the radiator.
3. After inserting the probe/switch through
the radiator core, install foam pad and
clip on probe and push until tight.
Note: Placement of the probe can affect
turn-on temperature. If you would like to
change the activation temperature, try
moving the probe/switch to a different
location on radiator.
