Symptom: left front door lock switch, lockout normal, unlock no.
    Fault diagnosis and troubleshooting: According to experience to judge, this fault phenomenon mostly switch or relay failure, so the use of parts maintenance method, the left front door lock lock power window switch replacement, the instrument under the control lock power window relay replacement does not work. The final judge for the line failure, in accordance with the circuit diagram check, the driver side of the central locking switch E150 to the central control lock control unit J379 only two lines, respectively, the yellow line control latch, gray black line control unlock, and the two lines in the line No plug connection. The use of multimeter block break directly measure the central locking switch E150 2 feet to the central locking control unit J379 8 feet off, the results show open, so the central control lock control unit J379 can not receive the central control lock switch E150 unlock signal. Will be the front door of the harness from the central relay pulled out to check whether the open circuit, found in the door hinge at the harness has a ground, the wiring harness repair troubleshooting.
    Symptom: ABS fault lights alarm, maintenance workers diagnosed for the ABS electronic control hydraulic unit failure, replacement failure remains the same.
    Fault diagnosis and troubleshooting: the car is to repair the ABS alarm, maintenance workers with VAG1551 after the diagnosis shows 01276 fault code, the contents of the fault code is ABS hydraulic pump V64 signal on the positive open circuit, due to Jetta ABS electronic control hydraulic unit More trouble, so maintenance workers did not think, to replace the ABS electronic control hydraulic unit, but the ABS fault lights are still alarm, but also 01276 fault code. Jetta ABS system has two 30A insurance, in the central relay box above the tapping, one of which alone to the ABS hydraulic pump V64 power supply, the fault is not broken? So check the central relay box 30A above the insurance, there is not even a plug, will be inserted after a insurance, and then remove the fault memory VAG1551, ABS failure lights go out.
    Symptom: the car air conditioning after the blower switch to a block when the AC switch is lit, air conditioning work, and then blower switch to two, three, four gear, AC switch indicator light is off, sometimes AC switch indicator flashing Bright, the compressor is broken.
    Fault diagnosis and troubleshooting: According to the circuit diagram analysis failure, the fault point should be in the blower switch to the AC switch harness, remove the air conditioning panel, unplug the blower switch plug, when the harness shaking suddenly smoke from the instrument, There is a place to wear ground. Remove the battery pile head, check the instrument after the line and found that the blower after the wiring harness and instrument table metal stent collision, long-term vibration harness was ground, the wiring harness repair fixed, troubleshooting. Many of the new interior car after the blower wiring harness is very tight, it is likely to cause such failures.