AfterMarketNews Auto Care Pro AutoProJobs Auto-Video.com Brake&Frontend BodyShopBusiness Counterman EngineBuilder Fleet Equipment ImportCar Motorcycle & Powersports News Servicio Automotriz Shop Owner Tire Review Tech Shop Tomorrow's Tech Underhood Service

Second-rate parts mean second-rate results

When it comes to diagnosing a problem, one of the biggest mistakes is thinking that the problem is gone after you’ve installed a new part. I’ve had vehicles brought in countless times with the same old story attached to them. The customer will say:...

Read more...

GearWrench Launches Street Team, a New Mobile Driver Program

GearWrench, a premier hand tool brand from Apex Tool Group, has announced Street Team, a new program that gives independent mobile distributors the support of an established tool brand without the restrictions of a franchise. "Response to the program...

Read more...

AUTO 7 Named Approved Vendor For Automotive Parts Associates

Steven Kruss, president of Auto 7, which supplies Korean-made, OEM-quality automotive parts to distributors across North America, announced that Auto 7 has been named an approved vendor of Automotive Parts Associates (APA), one of the nation’s...

Read more...

Internal Engine Oil Consumption Diagnostics

Due to the variables in engine design and ­operating conditions, internal engine oil ­consumption complaints are often the most difficult to solve. In some cases, oil consumption might be more severe under low-speed operation, in other cases, high-speed...

Read more...

Hyundai Fuel System, Emissions Diagnostics

Hyundai has done a good job of improving its ­offerings over the years from both an aesthetic and mechanical viewpoint. Complemented by a strong warranty and good value, the carmaker has been able to increase its market share year over year. If you aren’t...

Read more...

Curing Volvo Manual Transmission Rattle

In an effort to increase fuel efficiency, today’s engines produce more torque so they can be ­driven at extremely low rpm. ­Reduced viscosity engine and gearbox oils, less vehicle weight and improved aerodynamics also contribute to better fuel economy....

Read more...

Servicing The Electronically Adjustable Shocks Of Full-Sized GM Trucks

Since the 2000 model year, GM has offered electronically adjustable suspension as an option on Chevy, Cadillac and GMC full-size trucks. The system actuates the valving in the shocks to control ­suspension position and body attitude. The electronic...

Read more...

Diagnosing Clutch Assembly Noises

Noise can resonate from many areas of a ­vehicle’s driveline. There are several types of noises associated with the clutch assembly. The release bearing is most often blamed for being the cause of noise when, in many cases, it is not the release...

Read more...

Making Sense Of Steering Angle Sensor Input And Data

Measuring the­ ­position angle, rate of turn and force of the steering wheel is critical for Electronic Stability Control (ESC) systems. Scan tools call these Steering Angle Sensors (SAS) and typically display the information in degrees. The SAS...

Read more...

Victor’s Cash Back Program Makes Select Welders and Plasma Cutters More Affordable

Victor Technologies has launched its Cash Back Rebate program for customers in the United States and Canada. Between July 1 and Dec. 31, 2014, purchasers of select Tweco and Victor Thermal Dynamics systems can receive between $50 and $450 cash back....

Read more...

AVI To Provide Technicians with $1 Million in Free Training

AVI (Automotive Video Innovations) is giving back to the automotive community that has given so much opportunity to the Florida-based video company. To carry out that mission, AVI reports that it is pledging to give away $1 million worth of training...

Read more...

GearWrench Launches Street Team, a New Mobile Driver Program

GearWrench, a premier hand tool brand from Apex Tool Group, has announced Street Team, a new program that gives independent mobile distributors the support of an established tool brand without the restrictions of a franchise. "Response to the program...

Read more...

Home Climate Control Tech Tip: Volkswagen Has No Power to the A/C Compressor Clutch

Print Print Email Email

Vehicle Application: 2000 Beetle 2.0, 2002 Beetle 1.9, 2002 Golf 1.8, 1999-2003 Golf 2.0, 2000-’05 Jetta 1.8, 1.0, 1999-2005 Jetta 2.0 and 2000-’02 Jetta 2.8

Customer Concern: The A/C is not working. There is no power to the A/C compressor clutch and it does not engage. (Manual climate control.)

Potential Causes: A/C Compressor, A/C Pressure Sensor F129, A/C Switch, Ambient Temperature Switch F38, Battery Auxiliary Fuse Box, Fan Control Module J293 (and Wiring), Fuse or Lost Throttle Basic Settings

Tests/Procedures:

Test the Fan Control (FCM) module inputs as follows:

1. All tests are performed with the ignition key and A/C switched on and the connectors connected to the fan module. The fan control module is located under the radiator and has two connectors: a 14-pin (T14) and a 4-pin (T4).

2. Check for 12 volts to pin T4a/1 (red/black) and T4a/3 (red) via fuses S164 and S180 respectively, in the fuse box on top of the battery, at all times. (Note: It’s critical to check these power sources in a loaded condition as damage to the battery auxiliary fuse box can cause a loss of voltage under load. Visually inspect the condition of the three push-in type fuses for corrosion and burn marks.)

3. Verify an approximate 70% duty cycle from the A/C pressure sensor at pin T14/2 (white) with the ignition on and the compressor not running (duty cycle will decrease as the high-side pressure increases). A duty cycle above 80 or below 10 will command the compressor off and would indicate a faulty pressure sensor, if the compressor is not running and the refrigerant levels are normal.

4. Verify 12 volts to pin T14/4 (red/gray) via fuse 16, at all times.

5. Verify good ground to pin T14/6 (brown/black).

6. When the A/C is switched on and the blower motor is running at any speed, verify that 12 volts from the A/C switch in the instrument panel is available to pin T14/8 (blue/red). Note: The cooling fans should run at low speed whenever the A/C is switched on.

7. Verify 12 volts to pin T14/9 (black/blue) from fuse #5, when the ignition is in the “on” position.

8. Verify the presence of an 11-volt reference (actual voltage reading will oscillate between 7, 9 and 11 volts) at pin T14/13 (purple/yellow). The instrument cluster will ground this reference to request a compressor shutdown for an overheat condition. The cooling fans will also be running on high speed.

9. Disconnect the 14-pin connector. Using a fused 12-volt jumper, apply power to pin T14/10 (green/black). The compressor clutch should engage. If the compressor does not engage, check for a wiring harness open circuit or loss of ground at the compressor. Reconnect the 14-pin connector.

10. Disconnect the 14-pin connector and verify continuity between pin T14/14 (green/blue) and T14/5 (blue/red). This checks the Ambient Temperature Switch (ATS) (normal open circuit below 32° F, continuity above 32° F).

11. Verify the presence of an 11-volt reference voltage at pin T14/3 (green). The engine control module (ECM) will ground this reference to request a compressor shutdown for a wide open throttle (WOT) condition or lack of throttle basic setting. Eleven volts is the normal expected reading at this pin.

12. If all tests pass, the FCM is faulty and must be replaced.

Tech Tips:

Note: Pin T14/3 will be grounded by the ECM if the throttle basic settings are lost. Raising the engine rpm over 2,500 will cause the ECM to allow A/C operation if this is the case. If a ground condition exists on pin 3, perform a throttle basic setting procedure and recheck for correct voltage.

If needed, a repair kit is available from Volkswagen to replace the 14-pin fan control module connector, P/N 6X09737717 KIT.

Courtesy of Identifix.

The following two tabs change content below.
Advertisement
Advertisement
Advertisement
Advertisement
Latest articles from our other sites:

New Snap-on Shop And Tech Catalog: The Latest Innovative Essentials

Having the most up-to-date shop and tech equipment is not a luxury; it is a necessity to compete in today’s marketplace. The new Snap-on Shop and Tech catalog provides Snap-on customers with the most...More

Spectra Premium Introduces 93 New SKUs

Spectra Premium’s latest product release includes 93 new SKUs, covering more than 54 million vehicles on the road today. The new part numbers include radiators, filler necks, oil pans, fuel tank straps...More

Internal Engine Oil Consumption Diagnostics

Due to the variables in engine design and ­operating conditions, internal engine oil ­consumption complaints are often the most difficult to solve. In some cases, oil consumption might be more severe...More

Hyundai Fuel System, Emissions Diagnostics

Hyundai has done a good job of improving its ­offerings over the years from both an aesthetic and mechanical viewpoint. Complemented by a strong warranty and good value, the carmaker has been able to...More

Avoid The 'Warped Rotors' Trap, Find True Pulsation Cause

The expression “warped rotors” still seems prevalent in the brake service community. According to common lore, a warped rotor is the usual cause for pedal pulsation or vibration in the car or steering...More

Getting An Accurate Toyota Tire Pressure

Ambient temperature changes can dramatically alter tire pressure, which could cause a tire pressure monitoring system (TPMS) warning light to illuminate. The TPMS must be initialized based on the tire’s...More

Victor’s Cash Back Program Makes Select Welders and Plasma Cutters More Affordable

Victor Technologies has launched its Cash Back Rebate program for customers in the United States and Canada. Between July 1 and Dec. 31, 2014, purchasers of select Tweco and Victor Thermal Dynamics...More

‘Smart’ CTEK Battery Analyzer Ready To Work

CTEK has released its latest battery system accessory, the CTEK Battery Analyzer. All types of 12V batteries can be easily and quickly tested with high accuracy for their condition. The CTEK Battery...More