AfterMarketNews Brake&Frontend BodyShopBusiness Counterman EngineBuilder Fleet Equipment ImportCar Motorcycle & Powersports News Servicio Automotriz Shop Owner Tire Review Tech Shop Tomorrow's Tech Underhood Service Speedville

Servicing Mercedes-Benz AIRMATIC Suspensions

The Mercedes-Benz AIRMATIC suspension system was introduced in 1999 on the S-Class and has subsequently been used on the E-Class and most of the automaker’s SUVs. The system employs electronically controlled air springs that provide an ideal balance...

Read more...

Mazda: Performing Regular Undercar Maintenance

In this article, we’ll take a look at brake and undercar service on the Mazda vehicle lineup, with the footnote that even though this type of work ­becomes routine when you have a preventive maintenance mindset, good work habits from beginning to end...

Read more...

ZF 8-Speed Transmission Replacement

The ZF 8HP transmission made its debut in 2009, and since its introduction, has been one of the top choices for international car manufacturers. BMW, one of ZF’s largest customers, uses the 8HP across its entire product portfolio. BMWs featuring...

Read more...

Ford Edge Brake Replacement

Ford Edge Brake Replacement Basics The Ford Edge is an SUV based on the CD3 platform. The brakes on these vehicles are straightforward and do not break any new ground. There were no major changes to the brake systems from 2007 to the current model. For...

Read more...

Live-Axle Wheel Bearing Replacement

Replacing wheel bearings on a vehicle with a live rear axle may not be one of the most frequent jobs, but it can be one of the most profitable. While the basics have not changed in more than 60 years, new seal materials and differential designs have...

Read more...

Honda Civic Alignment Spec: 2006-'11

Built on a high-rigidity unit-body platform, the 2006-2011 Civic has a MacPherson strut front ­suspension and a multi-link rear suspension. The eighth generation switched from a high mounted to a low mounted steering rack and significantly increased...

Read more...

The Ins And Outs Of Sanders

Sanders are required tools in today’s collision repair shop. Body techs and painters rely upon them every day to achieve that perfect finish on your customers’ vehicles. Whether you’re prepping a panel for paint or removing imperfections before...

Read more...

Are You Regularly Maintaining Your Equipment?

Technicians who are idling because the welder won’t feed wire, the hydraulic ram won’t pull chains, the booth heater won’t heat or the air compressor won’t compress enough air is a costly mistake, as labor time is the most expensive thing in any...

Read more...

Celebrate 'Back To The Future' Day By Watching The Time Machine Get A 2015 Detail

    For many today is just another Wednesday, but for a lot of people it is more than just your average Wednesday, it is "Back to the Future" Day. It is a day that everyone who watched the cult classic trilogy Back to the Future recognizes...

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.
Latest articles from our other sites:

University Of The Aftermarket Foundation Introduces New Website

The University of the Aftermarket Foundation has launched a new website at UofAFoundation.com. The new site features the foundation’s mission, latest news and donor information. The new site also was...More

Bumper To Bumper Hosts The 'Bridge To Excellence Conference' In Little Rock, Arkansas

Bumper to Bumper recently hosted its 2016 Bridge to Excellence Conference in Little Rock, Arkansas. More than 500 people were in attendance, including 392 employees representing 163 stores from Crow-Burlingame,...More

Subaru/Honda: Rear Rotor Rubbing On Backplate After Installation

On some Subarus, Hondas and other vehicles utilizing a “drum-in-hat” type parking brake system operated in a corrosive environment (road deicers, salt, etc) the new rear brake rotor may rub against...More

Monroe Brakes 'Safety & Savings' Promotion Offers Consumer Rebates Of Up To $30

Consumers can earn a Visa Prepaid Card* of up to $30 when they replace their worn brake pads with Monroe Brakes products this spring. Available April 1 through May 31, 2016, the Monroe Brakes “Safety...More

Hunter's Road Force Elite Features Patented Vision System

The new Road Force Elite is Hunter’s fastest diagnostic wheel balancer and performs both a traditional balance and Road Force Measurement in less time than it takes to complete a conventional balance,...More

Streamlight Debuts Lithium Ion Battery and Charger

Streamlight Inc. introduced its 18650 Lithium Ion Battery and Charger, designed to energize the growing line of Streamlight products that accept 18650 rechargeable batteries. The new, dual power input...More