We need the manifold gauge readings, both high and low, and the air temp and humidity. I also suggest getting the codes read, Here's how:
Preliminary Information 1. Read ENTERING/EXITING SELF-DIAGNOSTICS . 2. Perform PRELIMINARY CHECK for appropriate vehicle symptom. See appropriate TROUBLE SHOOTING charts following this article. PRELIMINARY CHECK charts will direct technician to appropriate SELF-DIAGNOSIS STEP or appropriate DIAGNOSTIC PROCEDURE chart(s). 3. Perform appropriate SELF-DIAGNOSIS STEP under TROUBLE SHOOTING, or go to appropriate DIAGNOSTIC PROCEDURE in appropriate TROUBLE SHOOTING charts following this article. ENTERING/EXITING SELF-DIAGNOSTICS 1. To enter self-diagnostic mode, turn ignition off. Without starting engine, turn ignition on. Press vent button on A/C-heater control panel for at least 5 seconds. If engine starts, press vent button within 10 seconds after engine has started. 2. There are 5 SELF-DIAGNOSIS STEPS and one AUXILIARY MECHANISM TEST. The AUXILIARY MECHANISM TEST checks the temperature setting trimmer. If diagnostics are entered without engine running, SELF-DIAGNOSIS STEP 4 and SELF-DIAGNOSTIC STEP 5 cannot be completed. 3. To move from one diagnostic step to another, rotate temperature switch. To move from SELF- DIAGNOSIS STEP 5 to AUXILIARY MECHANISM TEST, press fan switch. On all models, to exit self-diagnostics, press AUTO button or turn ignition off. SELF-DIAGNOSIS STEP 1 Checks LEDs & Segments To perform LED and segment check, set temperature switch to position "A". See Fig. 1 or Fig. 7 . Repair or replace if necessary. Fig. 7: Identifying Temperature Switch Positions Courtesy of NISSAN MOTOR CO., U.S.A. SELF-DIAGNOSIS STEP 2 Checks Sensor Circuits For Open/Short Circuits 1. With system in SELF-DIAGNOSIS STEP 1 , set temperature switch to position "B" to enter SELF-DIAGNOSIS STEP 2. Fluorescent display will illuminate a "2". If all sensor circuits are okay, display will change to "20" after approximately 4 seconds. NOTE: Perform SELF-DIAGNOSIS STEP 1 before proceeding to any test to ensure that LEDs and segments illuminate, to help prevent misdiagnosis. 2. If a sensor circuit is faulty, circuit code number will flash on display. Shorted circuit will have a flashing "-" in front of the number 2. Open circuit will NOT have a flashing "-". For example, if number "21" is displayed on A/C-heater control panel ("2" will stay lit, and "1" will flash on and off), an open circuit is indicated. 3. If 2 sensor circuits are faulty, each code number will flash twice. To interpret codes, see SELF-DIAGNOSIS STEP 2 CODE EXPLANATIONS table.
SELF-DIAGNOSIS STEP 3 Checks Mode Door Position 1. With system in SELF-DIAGNOSIS STEP 2 , set temperature switch to position "C" to enter SELF-DIAGNOSIS STEP 3. Fluorescent display will illuminate a "3". If all doors are in good order, display will change to "30" after approximately 20 seconds. 2. If a door is faulty, it will be identified by another number illuminated to the right of "3". If 2 doors are faulty, each code number will blink twice. To interpret codes, see SELF- DIAGNOSIS STEP 3 CODE EXPLANATIONS table. NOTE: If any mode door motor position switch is malfunctioning, mode door motor also will malfunction.
SELF-DIAGNOSIS STEP 4 Checks Operation Of Each Actuator 1. With system in SELF-DIAGNOSIS STEP 3 , set temperature switch to position "D" to enter SELF-DIAGNOSIS STEP 4. Fluorescent display will illuminate a "41". Each time defrost button is pressed, fluorescent display to right of "4" will advance one number, up to "46". 2. After "46", the numbers begin again at "41". As numbers advance, the commands will change air intake and outlet routes. A visual and physical inspection must be made to ensure doors are switching properly. To determine proper door positions for each code, see SELF- DIAGNOSIS STEP 4 CODE EXPLANATIONS table.
Checks Temperature Detected By Sensors & Multiplex Communication Error 1) With system in SELF-DIAGNOSIS STEP 4 , set temperature switch to position "E" to enter SELF-DIAGNOSIS STEP 5. Fluorescent display will illuminate a "51". When defrost button is pressed once, fluorescent display will show temperature detected by ambient sensor. 2) Press defrost button again. Fluorescent display will show temperature detected by in-vehicle sensor. Press defrost button again. Fluorescent display will show temperature detected by intake sensor. 3) Press defrost button again. Fluorescent display again will illuminate "51". If temperature shown on fluorescent display differs greatly from actual temperature, inspect sensor circuit. If sensor circuit is okay, go to TESTING. 4) Press rec button. If multiplex communications are functioning properly, fluorescent display will illuminate "52". If "fan" symbol illuminates to right of "52", a past or current multiplex communication error between A/C-heater control panel and auto amplifier exists. 5) Disconnect negative battery cable for at least one minute to clear communication memory. Reconnect battery cable. Perform SELF-DIAGNOSIS STEP 5. If multiplex communication error still exists, go to DIAGNOSTIC PROCEDURE 1 . See appropriate TROUBLE SHOOTING charts following this article. AUXILIARY MECHANISM TEST Temperature Setting Trimmer 1. Temperature setting trimmer compensates for small differences between temperature setting (fluorescent display) and temperature felt by passengers in a range of plus or minus 6 F. With system in SELF-DIAGNOSIS STEP 5 , press fan button to enter auxiliary mode. 2. Rotate temperature control switch left or right, to change temperature setting on flourescent display. Temperature can be changed in one-degree increments. If vehicle battery is disconnected, temperature setting goes to 0 F.
Friday, July 9th, 2010 AT 4:16 PM