NO.4 AIR FROM VENTS COLD ENOUGH

id070300000100

4

Air from vents not cold enough.

DESCRIPTION

• Magnetic clutch operates but A/C system malfunctions.

POSSIBLE CAUSE

• Drive belt malfunction
• Malfunction in blower unit or condenser
• Malfunction in receiver/drier
• Malfunction in refrigerant lines
• A/C compressor system malfunction, insufficient compressor oil
• Over filling of compressor oil, malfunction in heater unit air mix link system

Diagnostic procedure

Step

Inspection

Inspection item (s)

1

INSPECT DRIVE BELT

• Inspect drive belt.
• Is it normal?
Yes
Go to next step.
No
Adjust or replace drive belt, then go to Step 18.
2

INSPECT REFRIGERANT SYSTEM PERFORMANCE

• Perform refrigerant system 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 18. (If air does not reach evaporator within cooling 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 normal?
Yes
Adjust refrigerant to specified amount, then go to Step 18. (Excessive amount of refrigerant.)
No
Replace condenser, or repair and clean condenser fins, then go to Step 18.
6

CHECK TO SEE WHETHER MALFUNCTION IS IN 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 13.
7

CHECK TO SEE WHETHER MALFUNCTION IS IN 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 9.
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 min.
• 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 30 min or more by vacuum pump, add refrigerant to specified level, then go to Step 18. (Since water has intermixed in receiver/drier and it is saturated, replacement is necessary.)
9

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 cooling unit free of gas leakage?
- Perform gas leak inspection using gas leak tester.
• Are above items normal?
Yes
Go to next step.
No
If piping or A/C component (s) are damaged or cracked, replace them.
Then go to Step 18.
If there is no damage, go to Step 12.
10

INSPECT EVAPORATOR PIPING CONNECTIONS IN COOLING UNIT FOR GAS LEAKAGE

• Are piping connections for evaporator in cooling 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 18.
No
If piping is damaged or cracked, replace it.
Then go to Step 18.
If there is no damage, go to next step.
11

INSPECT EVAPORATOR PIPING CONNECTIONS IN COOLING UNIT FOR LOOSE

• Are piping connections for evaporator in cooling unit loose?
Yes
Tighten connections with specified torque, adjust both compressor oil and refrigerant to specified amount, then go to Step 18.
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.
12

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 18.
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 18.
13

CHECK TO SEE WHETHER MALFUNCTION IS IN 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 16.
14

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.
15

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 18. (Cause is defective A/C compressor.)
16

CHECK TO SEE WHETHER MALFUNCTION IS IN ELSEWHERE

• Is only refrigerant low-pressure value high?
Yes
Go to Step 18.
No
Go to next step.
17

VERIFY THAT AIR MIX IS INSTALLED SECURELY AND PROPERLY

• Are heater 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 min.
(2) Run the engine at idle for 1 min.
(3) Within 12 s, idle → 4,000 rpm → idle. Perform cycle 5 times.
(4) Run the engine at idle for 30 s.
(5) Drain the compressor oil completely from the A/C compressor and verify the amount.
• If there is approx. 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 18.
18

VERIFY THAT MALFUNCTION SYMPTOM OCCURS AFTER REPAIR

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