Derale 16738 - User Manual

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.

Summary

Relay and Wire Harness Installation

Mount Relay and Wire Harness

Mount the relay/wire harness in a convenient location, avoiding hot components.

Secure Relay;Wire Harness

Drill a 3/16" hole and use a #14 metal screw to mount the relay/wire harness.

Thermostat Probe Installation

Attach Brass Probe to Switch

Thread the brass probe onto the thermostat switch before installation.

Insert Probe into Radiator Core

Insert the probe/switch between radiator fins near the water inlet until flush.

Secure Probe with Pad and Clip

Install the foam pad and clip onto the probe, pushing until tight.

Manual Switch Override

Manual Override Functionality

The AC override circuit can be used as a manual override if AC is not present.

Manual Override Diagram

Diagram shows connections for manual override using keyed ignition and relay green wire.

Troubleshooting

Fan Not Turning On

Steps to diagnose fan not turning on, checking voltage, engine temp, and connections.

Fan Runs with Ignition Off

Check yellow wire connection to ensure it's ignition switched.

Fan Activation Temperature Issues

Adjust probe placement further from the water inlet to change activation temperature.

Derale 16738 Specifications

General

Brand	Derale
Model	16738
Category	Thermostat
Language	English