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
