Here are some excerpts on the glow plug operation from manual. Didn稚 see anything specific on the R&R procedure.
ENGINE PREHEAT
CONTROLLER
TEST?55
AND 755/756
Open hood.
Use flashlight tester.
Place test light on glow
plug terminal (A).
Turn key switch ON.
LOOK: Dash lamp ON,
test light ON.
Dash lamp will be ON
for 9 seconds or less,
test light ON for 30
seconds or less.
Note: Hotter engine
temperatures will
reduce times that
lamps are ON.
OK: PREHEAT CONTROLLER
IS OK.
CHECK GLOW
PLUGS.
NOT OK: CHECK
FUSIBLE LINK
FROM STARTER TO
MODULE SOCKET
(RED WIRE).
REPLACE CONTROL
MODULE AS
NEEDED.
THERMO-START COMPONENTS
GLOW PLUGS (655 AND 755/756 MODELS ONLY): The
glow plugs (A) are located on the top of the engine
cylinder head, between the fuel injectors and the rocker
arms cover.
AIR HEATER (855/856 AND 955 MODELS ONLY): The
air heater element (B) is located in-line between the
engine air cleaner and the intake manifold.
Open hood and remove air cleaner canister and hose to
access either of them.
M47004 -UN-31AUG88 M47003 -UN-31AUG88
MX,24015HU,5 -19-16OCT91
MX,24015HU,6 -19-16OCT91
Theory of Operation/Thermo-Start Components Locations
TM1360 (16OCT91) 240-15-2 55, 56 Series Tractors
010395
240
15
2
The engine preheat circuit regulates current flow to
the glow plugs (655 and 755/756 models) or air
heater (855/856 and 955 models) used to assist in
cold weather starting.
Current flows from the battery (A) to the starter (B)
common terminal, the key switch (E) 釘AT terminal
and the control module (H) No. 2 terminal. The key
switch and control module connections contain
16-gauge fusible links (C and D).
When the key switch is in the ON or START position,
current flows through the 的GN terminal to the
10-amp (F), the dash mounted wait light (G), and the
control module (H) No. 3 terminal.
Current flows from the No. 3 terminal through the
module temperature sensor to ground (Terminal 3 to
1). The sensed value is a combination of air and
machine temperatures. When the sensed temperature
is below predetermined limits (cold weather), the
control module completes a path to ground which
lights the dash wait lamp (Terminal 5 to 1).
Internal switching also completes the battery to glow
plug/air heater circuit (Terminal 2 to 4).
The wait and heat times for the 655 and 755/756
models vary based on temperatures sensed by the
control module. The maximum wait light time is eight
seconds and the maximum glow plug heat time is 30
seconds.
The wait and heat times for the 855/856 and 955
models are constant. Whenever the sensed
temperature is below 4ｰC (40ｰF) the dash wait lamp
lights for 15 seconds and the air heater glows for 45
seconds.
The engine may be started after the dash wait lamp
goes out. Once the wait light goes out, the glow
plugs or air heater will remain on to assure smooth
engine start and warm up. The glow plugs or air
heater will turn off when the predetermined time or
temperature limit is reached.
M43868 -19-01MAY89
MX,24015HU,20 -19-16OCT91
Theory of Operation/Engine Preheat Circuit Operation
TM1360 (16OCT91) 240-15-11 55, 56 Series Tractors
