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Automotive air conditioning cooling fans are not normally open fault

sdate : 2013-05-23     penster : Shanghai Futailong     source : www.
Core Tip:an era of Superman car, turn the ignition switch failure phenomenon is electromagnetic clutch to work after the air-conditioning, cooling fan also Users reflect this failure was repaired in the repair shop, but the problem is

Fault 1: an era of Superman car, turn the ignition switch failure phenomenon is electromagnetic clutch to work after the air-conditioning, cooling fan also work. Users reflect this failure was repaired in the repair shop, but the problem is not resolved.

Take the car, I first unplug the A / C switch, the outdoor temperature switches, temperature control air conditioning relay switches and the 13th, the compressor is still working. For fast troubleshooting, we should clear this car air conditioning systems control theory. Based on the above control theory, first check the fan controller circuit, because the electromagnetic clutch is powered by its direct. However, according to the driver say that the car has been replaced a new controller, so it should be another switch signal is not normal. Disconnect the air pressure when the combination switch, air conditioning electromagnetic clutch to stop working. According to the schematic, shows high voltage switching power supply from the ignition switch. If the high pressure switch is a normally-on, then the air-conditioning system fan controller will recognize the normal air-conditioning systems at this time at high pressure, so it will turn the cooling fan and the compressor. Check the switch with a multimeter, the result is often pass.

When replacing a new pressure switch, troubleshooting.

Fault 2: an era of Superman sedan, air conditioning compressor work half a minute to stop working, but they immediately work, work for half a minute and then shut down, and so forth. At first I thought it was caused by system pressure, but with the pressure gauge measuring system pressure is normal. Since the system pressure is normal, then the problem should appear on the control circuit or component. In order to facilitate inspection, start the engine open the A / C switch, then repeated conditioning electromagnetic clutch pull-off, but the cooling fan has been operating normally. From the flow chart (Figure 2) can be seen: If the blower and cooling fan is working properly, the fault should be the outdoor temperature switch below the electrical circuit. To quickly find the point of failure, I decided to use test pencil first tested the engine compartment of the switches work performance. First test with test pencil between fan controller to the electromagnetic clutch wire, test pencil flashing, indicating a fault in the fan controller above the relevant circuit. Then switch to the fan from the outdoor temperature controller search from the middle section, dial combination air pressure switch, then pull the electromagnetic clutch stop, combined with test pencil test pressure switch low-voltage terminal lines, lit one end, one end does not shine. Turn off A / C switch, lit one end also will be powered down, the next question should be that this combination of air pressure switch low pressure switch to shut off air to the fan controller relay or between the lines or electrical components. Plugged pressure combination switch, open the A / C switch, combination switch with test pencil test pressure between the air conditioning circuit cut-off relay, test pencil lit, air-conditioned with a test pencil test circuit cut-off relay to the fan controller, test pencil flash a flash. Then you can determine the scope of failure is a broken appliance itself and line, and the line is generally not a problem, so first remove the breaker to replace testing, troubleshooting.

Open circuit breaker inspection found serious erosion has contacts, the contact surface is small, but what causes excessive current contacts it? After asking the user, that this car some time ago, just replaced air conditioning compressor, because the bearings "Hugging" Insurance Insurance fuse box air conditioning compressor also damaged. So far, the cause will get to the bottom. After replacing the air conditioning compressor and insurance fuse, although at that time the system can work, but as a result of irregular compressor locking, electromagnetic clutch will certainly slip, the coil current will be too large. Air conditioning cut-off relay, is the result of the last current caused serious damage to contacts, turned parts for a period of time due to increased temperature resistance increases lead to power outages, but energized, the temperature dropping resistor to reduce the circuit has been switched on , which appeared in the failure.



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