TM 5-2420-230-24-2
B3.9 and B5.9 Series Engines
Cold Start Timing Advance System (KSB) Temperature Switch (005-069)
Section 5 - Fuel System - Group 05
Page 5-99
CAUTION
The switches are not interchangeable. White smoke
will be present if the wrong temperature switch is used.
Check the part number to be sure the correct temperature
switch is used.
NOTE: The electrical solenoid-style KSB (used on '91 mod-
els and newer) uses a 32C [90F] normally closed intake
manifold temperature switch, Part No. 3921642.
Test (005-069-012)
Wax-Motor Style
The operation of the temperature switch for the wax motor
style KSB can be checked by connecting a multimeter to
the switch, placing the switch in water, and then heating the
water to 71C [160F].
Connect the multimeter to the two pins on the left when
viewed with the plastic tang on top.
Check the water temperature with a thermometer.
The multimeter should indicate an open circuit below 71C
[160F] and a closed circuit above 71C [160F].
Replace the switch, if necessary.
Electrical Solenoid Style
Although the electrical solenoid-style KSB uses an intake
manifold temperature switch, the operation of the switch
can be checked by connecting a multimeter to the switch,
placing the switch in ice water, and then heating the water
to 32C [90F].
Connect the multimeter to the two outside pins of the tem-
perature switch.
L-959
