Test Switch; Short Indicator - Intellitec ELECTROINC CLIMATE CONTROL Service Manual

ELECTRONIC CLIMATE CONTROL
The Control Module operates the air conditioner compressors and fans via three relays with 12 VDC coils
supplied by the A/C manufacturer and mounted in their equipment. The contacts on these relays are internally
wired by the A/C manufacturer to the 120 VAC supply line for each unit and connect the compressor and the
low or high speed taps on the fan motor to that supply line when operated. The wiring between the Control
Module and these relays is low voltage (12 VDC) wiring. The Control Module uses high side switching to
operate the corresponding relays. One side of each of the relay coils is connected together. This "common"
lead is connected to ground through the Control Module and should not be grounded anywhere else. The other
side of each of the coils is brought out to one of three separate leads. These leads are connected to the Control
Module via a four pin connector - J2 for the front A/C unit, and J3 for the rear A/C unit. The corresponding pigtail
connectors, PC2 and PC3, are supplied with the system. PC3, the rear A/C connector, is marked in red in
order to differentiate it from PC2. The following table indicates the connection and control states:
MODULE
CONN
PIN
J2-1
J2-2
J2-3
J2-4
J3-1
J3-2
J3-3
J3-4
NOTE: The PC2 and PC3 pigtail wire colors are included for reference only to identify the functions of
the wires emanating from the Control Module. The wire colors emanating from the front and rear
A/C units may or may not agree with these colors. Always refer to the installation manual
supplied with the A/C unit, or see "Identifying control lead functions on the A/C unit", in order to
match the wire color/functions with those on the Control Module.

TEST SWITCH:

The Control Module incorporates a three position test switch located between J2 and J3 to verify proper wiring
to each A/C unit relay. Sliding the test switch towards the J2 operates the front compressor and high fan by
connecting J2-3 and J2-4 to +12V. Sliding the test switch towards the J3 operates the rear compressor and
high fan by connecting J2-3 and J2-4 to +12V. The test switch must be placed in the CENTER or OFF position
for normal operation.

SHORT INDICATOR:

The 12 volt wires feeding the air conditioners are protected from short circuits. If any of these wires is shorted
to ground, the SHORT INDICATOR LED will be illuminated, indicating the short. To help locate the short, the
plugs feeding the air conditioners should be unplugged, one at a time, to see which cable is at fault. When the
shorted cable is unplugged, the SHORT INDICATOR will go out and the other air conditioner will operate
normally. The individual wires of the shorted plug can be tested for shorts to find which one is at fault.
INTELLITEC
PIGTAIL
WIRE FUNCTION
COLOR
BLU COMMON
GRY LOW FAN
GRN HIGH FAN
YEL COMPRESSOR
BLU COMMON
GRY LOW FAN
GRN HIGH FAN
YEL COMPRESSOR
"ON"
VOLTAGE
< 1 VDC
+12 VDC
+12 VDC
+12 VDC
<1 VDC
+12 VDC
+12 VDC
+12 VDC
131 EISENHOWER LANE NORTH
LOMBARD, ILLINOIS 60148-5413
630-268-0010 / 1-800-251-2408
5
"OFF"
VOLTAGE
< 1 VDC
< 1 VDC
< 1 VDC
< 1 VDC
< 1 VDC
< 1 VDC
< 1 VDC
< 1 VDC
53-22130A100