Derale DER-16749 Diagnostics Manual

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How To Diagnose DER-16749

First off, you must have access to a DIGITAL VOLT AND OHM METER

(DVOM). You cannot use a test light on the diagnosis of this unit. As with

any automotive electrical install, make sure your vehicle's battery is in

proper operating condition (12.5V or higher). If your battery is weak this can

cause functionality issues with the controller unit.

If your fan is not cutting on after install you will need to go over each

connection. Check continuity on each connection made. This will involve

you using the resistance or ohm setting on the DVOM before and after

each connection. If you show an open or OL reading, then you need to fix

this connection.

BLUE WIRES FROM FAN- These will go together and will be tied into the

12V battery voltage. Using the DVOM, verify you show 12.5V or more at

the batt when setting this up. Check continuity on each connection made

before and after each connection.

BLACK WIRES FROM FAN- These will go together and will be tied into the

red wire off of the controller. Check continuity on each connection made

before and after each connection

TEMP PROBE- The most accurate signal for this will be on the thermostat

housing. Putting this in any other location can cause issues with the fan

cutting on. If your kit did not include part number LRS-8592A then you will

need to incorporate this into your installation. LMR recommends to always

use this on a vehicle equipped with a thermostat. If your car is running an

open thermostat, the coolant may never reach the correct temp depending

on conditions.

YELLOW WIRE FROM CONTROLLER- This needs to be hooked up to a

valid 12V switched ignition circuit. Using your DVOM, you can go to your

Table of Contents

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Page 1 How To Diagnose DER-16749 First off, you must have access to a DIGITAL VOLT AND OHM METER (DVOM). You cannot use a test light on the diagnosis of this unit. As with any automotive electrical install, make sure your vehicle’s battery is in proper operating condition (12.5V or higher).
Page 2 fuse panel and find a 12V circuit that is only hot when the key is on. Do not hook this up to any circuits that have a full time key off 12V source. BLACK WIRE FROM CONTROLLER- This wire needs to be your ground connection.
Page 3 and that your thermostat is opening when intended. If you have access to a laser style thermometer, point this as close to the temp probe as you can on the housing. Try to get the fans cutting on as close to the thermostat opening point as you can.