NO.7 AIR FROM VENTS COLD ENOUGH

id070300801000

7

Air from vents not cold enough.

DESCRIPTION

• Magnetic clutch operates but A/C system malfunctions.

POSSIBLE CAUSE

• Drive belt malfunction (Step 2)
• Malfunction in blower unit or condenser (Steps 4, 5)
• Malfunction in receiver/drier or expansion valve (valve closes too much) (Steps 8, 9)
• Malfunction in refrigerant lines (Steps 10, 11)
• A/C compressor system malfunction, insufficient compressor oil (Steps 15, 16)
• Over filling of compressor oil, malfunction in expansion valve or A/C unit air mix link system (Steps 17-19)

Diagnostic procedure

STEP

INSPECTION

ACTION

1

INSPECT DRIVE BELT

• Inspect drive belt.
• Is it okay?
Yes
Go to next step.
No
Adjust or replace drive belt, then go to Step 20.
2

INSPECT REFRIGERANT SYSTEM PERFORMANCE

• Perform refrigerant system performance test.
• Is operation normal?
Yes
Operation is normal. (Recheck malfunction symptoms.)
No
Go to next step.
3

CHECK TO SEE WHETHER MALFUNCTION IS IN BLOWER UNIT INTAKE AND CONDENSER OR ELSEWHERE

• Are refrigerant high-pressure and low-pressure values both high?
Yes
Go to next step.
No
Go to Step 6.
4

INSPECT BLOWER UNIT INTAKE

• Is blower unit intake clogged?
Yes
Remove obstruction, then go to Step 20. (If air does not reach evaporator within A/C unit, heat exchange does not occur and refrigerant pressure becomes high.
Therefore, removal of obstruction is necessary.)
No
Go to next step.
5

INSPECT CONDENSER

• Inspect condenser.
• Is it okay?
Yes
Adjust refrigerant to specified amount, then go to Step 20. (Excessive amount of refrigerant.)
No
Replace condenser, or repair and clean condenser fins, then go to Step 20.
6

CHECK TO SEE WHETHER MALFUNCTION IS IN EXPANSION VALVE, RECEIVER/DRIER AND REFRIGERANT LINES OR ELSEWHERE

• Are refrigerant high-pressure and low-pressure values low?
Yes
Go to next step.
No
Go to Step 14.
7

CHECK TO SEE WHETHER MALFUNCTION IS IN EXPANSION VALVE AND RECEIVER/DRIER OR ELSEWHERE

• Immediately after A/C compressor operates, does refrigerant high-pressure value momentarily rise to correct value, then fall and stay below it? (Is there negative pressure on low-pressure side?)
Yes
Go to next step.
No
Go to Step 10.
8

CHECK TO SEE WHETHER MALFUNCTION IS IN EXPANSION VALVE OR RECEIVER/DRIER

• Turn A/C switch off and let air conditioner stop for 10 minutes.
• Start engine.
• Turn both A/C switch and fan switch on.
• Does malfunction occur after A/C compressor turns on?
Yes
Go to next step.
No
Replace condenser and vacuum refrigerant line more than 30 minutes by vacuum pump, add refrigerant to specified level, then go to Step 20. (Since water has intermixed in receiver/drier and it is saturated, replacement is necessary.)
9

VERIFY THAT EXPANSION VALVE HEAT-SENSING TUBE WITHIN A/C UNIT IS POSITIONED SECURELY AND CORRECTLY

• Is expansion valve heat-sensing tube within A/C unit securely installed in proper position?
Yes
Replace expansion valve, then go to Step 20. (Since valve closes too much, replacement is necessary.)
No
Install heat-sensing tube securely in proper position, then go to Step 20.
10

INSPECT REFRIGERANT LINES

• Inspect refrigerant lines.
- Is piping free of damage and cracks?
- Are piping connections free of oil grime? (Visual inspection)
- Are piping connections free of gas leakage?
- Are piping installation points on condenser free of gas leakage?
- Are piping installation points on receiver/drier free of gas leakage?
- Are piping installation points on A/C compressor free of gas leakage?
- Are piping installation points on A/C unit free of gas leakage?
- Perform gas leak inspection using gas leak tester.
• Are above items okay?
Yes
Go to next step.
No
If piping or A/C component(s) are damaged or cracked, replace them.
Then go to Step 20.
If there is no damage, go to Step 13.
11

INSPECT EVAPORATOR PIPING CONNECTIONS IN A/C UNIT FOR GAS LEAKAGE

• Are piping connections for evaporator in A/C unit free of gas leakage?
Yes
If the vane makes a noise, add 10 ml {10 cc, 0.34 fl oz} of compressor oil to the A/C compressor. Verify that the noise is no longer heard.
Adjust refrigerant to specified amount, then go to Step 20.
No
If piping is damaged or cracked, replace it.
Then go to Step 20.
If there is no damage, go to next step.
12

INSPECT EVAPORATOR PIPING CONNECTIONS IN A/C UNIT FOR LOOSE

• Are piping connections for evaporator in A/C unit loose?
Yes
Tighten connections with specified torque, adjust both compressor oil and refrigerant to specified amount, then go to Step 20.
No
If the vane makes a noise, add 10 ml {10 cc, 0.34 fl oz} of compressor oil to the A/C compressor. Verify that the noise is no longer heard.
Replace O-ring on piping, adjust refrigerant to specified amount, then go to Step 20.
13

INSPECT PIPING CONNECTIONS FOR LOOSE

• Are piping connections loose?
Yes
Tighten connections with specified torque, adjust both compressor oil and refrigerant to specified amount, then go to Step 20.
No
If the vane makes a noise, add 10 ml {10 cc, 0.34 fl oz} of compressor oil to the A/C compressor. Verify that the noise is no longer heard.
Replace O-ring on piping, adjust refrigerant to specified amount, then go to Step 20.
14

CHECK TO SEE WHETHER MALFUNCTION IS IN EXPANSION VALVE, AIR MIX ACTUATOR AND COMPRESSOR OIL OR ELSEWHERE

• Does refrigerant high-pressure value hardly increase?
Yes
Go to next step. (Pressure hardly increases.)
No
Go to Step 17.
15

CHECK TO SEE WHETHER MALFUNCTION IS IN COMPRESSOR OIL AMOUNT AND A/C COMPRESSOR OR ELSEWHERE

• When engine is racing, does high-pressure value increase?
Yes
Return to Step 3.
No
Go to next step.
16

CHECK TO SEE WHETHER MALFUNCTION IS IN COMPRESSOR OIL AMOUNT OR A/C COMPRESSOR

• After compressor oil is replenished each 10 ml {10 cc, 0.34 fl oz}, does high-pressure value increase?
Yes
Troubleshooting completed. (Explain to customer that cause was insufficient compressor oil.)
No
Replace A/C compressor, then go to Step 20. (Cause is defective A/C compressor.)
17

CHECK TO SEE WHETHER MALFUNCTION IS IN EXPANSION VALVE OR ELSEWHERE

• Is only refrigerant low-pressure value high?
Yes
Go to Step 19.
No
Go to next step.
18

VERIFY THAT AIR MIX IS INSTALLED SECURELY AND PROPERLY

• Are A/C unit air mix links, air mix cranks, and air mix rods securely and properly installed?
Yes
Set fan switch to 4th position.
Turn A/C switch on.
Set FRESH mode.
Set temperature control to MAX COLD.
Set VENT mode.
(1)Start and run the engine at 1,500 rpm for 10 minutes.
(2)Run the engine at idle for 1 minute.
(3)Within 12 seconds, idle → 4,000 rpm → idle. Perform cycle 5 times.
(4) Run the engine at idle for 30 seconds.
(5)Drain the compressor oil completely from the A/C compressor and verify the amount.
• If there is approximately 90 ml {90 cc, 3.0 fl oz} of compressor oil, go to Step 20.
• If there is more than 90 ml {90 cc, 3.0 fl oz} of compressor oil, remove surplus oil and fill A/C compressor with 90 ml {90 cc, 3.0 fl oz} of compressor oil. Repeat Steps (1) to (5).
(Cause is excessive amount of compressor oil.)
No
Repair or install links, cranks and rods securely in proper position, then go to Step 20.
19

VERIFY THAT EXPANSION VALVE HEAT-SENSING TUBE WITHIN A/C UNIT IS POSITIONED SECURELY AND CORRECTLY

• Is expansion valve heat-sensing tube within A/C unit securely installed in proper position?
Yes
Replace expansion valve, then go to next step. (Since valve opens too much, replacement is necessary.)
No
Install heat-sensing tube securely in proper position, then go to next step.
20

VERIFY THAT MALFUNCTION SYMPTOMS DO NOT RECUR AFTER REPAIR

• Does cool air blow out? (Are results of refrigerant system performance test okay?)
Yes
Troubleshooting completed.
Explain repairs to customer.
No
Recheck malfunction symptoms, then repeat from Step 1 if malfunction recurs.