Coolant Heater - Check; Oil Pressure Switch/Sending Unit - Check; Coolant Temperature Sensor - Check - Dodge D250 1990 Service Manual

Electrical System
DODGE Turbo Diesel
Diagnosing Electrical Malfunctions
Page 8-11
Oil Pressure Switch/Sending Unit - Check
Remove the pressure switch, install a gauge, start the engine > ^
and measure oil pressure. Minimum oil pressure:
Idle 6 9 k P a [10 psi]
Rated Speed 207 kPa [30 psi]
Note: The Pressure switch is set to actuate when oil pressure
drops to 55 k P a [8 P S I ] . The pressure switch wilt activate a
L o w P r e s s u r e Warning Light on the dash of the truck.
Coolant Temperature S e n s o r - C h e c k
R e p l a c e the s e n s o r a n d rerun engine to confirm the
temperature.
Coolant Heater - Check
W h e n operating, the engine block heater should make an
audible sound and the adjacent parts should be warm to the
touch.
The heater will operate continuously when plugged into the
c o r r e c t voltage electrical s o c k e t (110 volt A . C , 6.5 a m p ) .
Operate only when the ambient temperature is below 4 ° C [40°
F].
4°c;