Suzuki XL7 2007 Service Manual page 1850

7A-36 Heating, Ventilation and Air Conditioning:
Circuit/System Testing
1. Ignition OFF, disconnect the A/C Relay.
2. Ignition ON, verify that a test lamp does not
illuminate between the controlled output circuit, and
ground.
➢ If the test lamp illuminates, test the releay
controlled output circuit for a short to voltage.
3. Verify that a test lamp illuminates between the relay
ignition circuit, and ground.
➢ If the test lamp does not illuminate, test the ignition
circuit for a short to ground or a open/high
resistance. If the circuit tests normal and ignition
circuit fuse is open, test or replace the A/C
Compressor Clutch Relay.
4. Verify that a test lamp illuminates between the relay
switch B + circuit, and ground.
➢ If the test lamp does not illuminate, test the relay
switch B + circuit for a short to ground or a open/
high resistance. If the circuit tests normal and the
relay coil B + circuit fuse is open, test the relay
ignition output circuit for a short to ground.
➢ If the test lamp does not illuminate, test the relay
switch ignition circuit for an open/high resistance.
5. Disconnect the harness connector at the A/C
Compressor Clutch Coil.
6. Test for less than 1 ohm of resistance between the A/
C Compressor Clutch Coil terminal B ground circuit
terminal and ground.
➢ If greater than 1 ohm, test the ground circuit for an
open/high resistance.
7. Connect the harness connector at the A/C
Compressor Clutch Coil.
8. Connect a 3-amp fused jumper wire between the
relay switch B+ circuit and the relay controlled output
circuit. Verify the A/C Clutch Relay is activated.
➢ If the A/C Compressor Clutch Relay does not
activate, test the relay controlled circuit for an open/
high resistance. If the circuit tests normal, test or
replace the A/C Compressor Clutch Relay.
9. Connect a test lamp between the relay coil ignition
circuit, and the relay coil control circuit.
10. Command the A/C Relay output function ON and
OFF with a scan tool. The test lamp should turn ON
and OFF when changing between the commanded
states.
➢ If the test lamp is always ON, test the control circuit
for a short to ground. If the circuit tests normal,
replace the ECM.
➢ If the test lamp is always OFF, test the control
circuit for a short to voltage, or an open/high
resistance. If the circuit tests normal, replace the
ECM.
11. If all circuits test normal, test or replace the A/C
Compressor Clutch Relay.
Component Testing
Relay Testing
1. Ignition OFF, disconnect the A/C Compressor Clutch
Relay.
2. Test for 137 ohms across the relay coil B+ and relay
coil output controlled circuits.
➢ If the resistance is not close to the specified range,
replace the relay.
3. Test for infinite resistance between the following
terminals:
➢ relay switch B+ and the relay switch controlled
output.
➢ If less than infinite resistance, replace the relay
4. Install a 20-amp fused jumper wire between relay
coil B+ and 12 volts. Install a jumper wire between
relay coil control and ground. Measure for less than
2 ohms of resistance between the relay switch B +
circuit and relay switch controlled output circuit.
➢ If greater than 2 ohms, replace the relay.
Repair Instructions
Perform the "Diagnostic Repair Verification - Vehicle
Diagnostic Information: " after completing the diagnostic
procedure.
• "Control Module References: " for ECM setup,
replacement, and programming.
• "Relay Replacement (Within an Electrical Center): "
"Relay Replacement (Attached to Wire Harness): "
Symptoms - HVAC Systems - Automatic
NOTE
Review the system operation in order to
familiarize yourself with the system
functions. Refer to the following procedures:
• "Air Delivery Description and Operation"
• "Air Temperature Description and
Operation"
Visual/Physical Inspection
• Inspect for aftermarket devices which could affect the
operation of the HVAC System. Refer to "Checking
Aftermarket Accessories: ".
• Inspect the easily accessible or visible system
components for obvious damage or conditions which
could cause the symptom.
• Verify the A/C compressor clutch turns freely and is
not seized.
• The A/C compressor will not operate in cold outside
air temperatures. Refer to "Air Temperature
Description and Operation".