Thermo King SB-210, Manual

Page: 73 / 159

Electrical Maintenance
73
a. The three wires from the PSM should be
connected to the heater contactor terminals
as follows: Brown wire to terminal L1,
Blue wire to terminal L2, and Black wire
to terminal L3.
b. Wires L1, L2, and L3 should be connected
respectively to terminals L1, L2, and L3
on the heater contactor and both motor
contactors.
c. Wires T1A, T2A, and T3A should be
connected respectively to terminals T1,
T2, and T3 on MC1.
d. Wires T1A, T2A, and T3A should be
connected respectively to terminals T3,
T2, and T1 on MC2.
e. Wires T1A, T2A, and T3A should be
connected respectively to terminals T1,
T2, and T3 on the overload relay.
f. Wires T1 & T7, T2 & T8, and T3 & T9
should be connected respectively to
terminals T1, T2, and T3 on the overload
relay.
g. Wires Black, Blue, and Brown should be
connected respectively to terminals 3, 4,
and 5 in the power receptacle.
h. Wires Brown, Blue, and Black should be
connected respectively to terminals L1,
L2, and L3 on MC1.
i. The 9-pin wire connector between the
PSM and the wire harness should be clean
and tight.
j. The electric motor must be wired
correctly.
2. Check MC1 and MC2 to make sure that one of
them is not faulty (contacts stuck closed).
3. If all of the wiring is correct, and the relays
and contactors are acceptable, but the electric
motor still runs backwards, switch the Brown
wire and the Black wire from the PSM at the
heater contactor: Black to L1, Blue to L2, and
Brown to L3. If the electric motor now runs
correctly, it is probably wired incorrectly.
If the electric motor does not run at all:
1. Make sure that the unit is turned On, that
Electric Standby has been selected in the
Operator Menu, and that the power supply is
connected and turned On.
2. Check the CH wire to the PSM for continuity
to the CH circuit (chassis ground). If there is
no continuity to the CH circuit, check the CH
wire for continuity.
3. Check for battery voltage (12 volts) at the
7EA wire to the PSM. Battery voltage should
be present. If not, check the 7E circuit, the
diesel/electric relay (K5), the run relay (K1),
the 8 circuit, the Microprocessor On/Off
switch, the 2AB circuit, the F2 fuse, the 2
circuit, the fuse link, and the battery. Also
make sure that the microprocessor display is
on and that the microprocessor is calling for
Heat or Cool.
4. Check for battery voltage at the 7EB and 7EC
wires at the PSM. Battery voltage should be
present on one of these wires when the correct
AC voltage is present on L1, L2, and L3. If
battery voltage is not present, the PSM is
faulty.
5. Check for battery voltage at the 7EB terminal
on MC1 and at the 7EC terminal on MC2.
Battery voltage should be present at one of
these terminals. If not, check the continuity of
the 7EB and 7EC wires.
6. Check the continuity of the RED wires on the
motor contactors. The RED wires must have
continuity.
7. Check the CH circuit at MC1 and MC2 for
continuity to a chassis ground. If the CH
circuits do not have continuity to a chassis
ground, check the CH wires.
8. Check the continuity of the BLK wires on the
motor contactors. The BLK wires must have
continuity.
9. If the CH circuits and BLK wires do have
continuity to CH, the contactor that has
battery voltage present at 7EB (MC1) or at
7EC (MC2) is faulty.