My garage gets a VW Magotan car which has run 102,000 km. The driver reflects that when the air condition is on, the blower stops working, but others works normally.
Check the car with
VAS 5054, and read the trouble code 01273. It shows that in the air condition system, the flesh air fan V2 cuts off or it has short circuit to positive pole. The trouble fails to be erased. Measure the blower resistance; it is 0.5 Ω, which shows that blower is normal.
Use function03 to conduct the self-diagnosis of execute components. It fails to activate the blower. Take out the blower control unit. After measuring, I find that there is no positive power in it. According to the circuit diagram, I find out the blower fuse wire SC39, it is good. But I measure it and find that SC39 does not have 12V voltages. So I connect the power to SC39 directly, the blower can work. It means that the trouble is located in the circuits instead of air condition. There is only fuse wire SC39 in the air condition circuits, and no signs about the source of SC39. According to the basic appliances on the circuit diagram, I find that the electric source of SC39 is J519. Take out the plug T2CP of J519. It does not have 12V voltages. It shows that maybe J519 has no trouble; the trouble may be located in the other appliances.
Look at the circuit diagram again, I find that the power line is from SB29. Check the SB29. One of its plugs has poor connection. Change the E-box, the trouble is figured out. But, meanwhile, the radio cannot turn on, and the indoor light is not on. Enter the 2nd area of 19-08-00 with the VAS 5054, activation begins. It means that the transportation mode is open. Turn off the transportation mode, and then the trouble is erased successfully.