2. Circuit Analysis First, when the ignition switch is turned to IG2 and the air conditioner pressure switch is pressed, the coil of the condenser fan relay is energized to form a loop, and the current direction is: battery positive → hood under fuse/relay box Fuse No.41, No.42→White line→Ignition switch (BAT→IG2)→Yellow line→Fuse No.13→Black/yellow line→Condenser fan in the fuse/relay box under the driver's seat side panel Relay coil → green line → air conditioning diode → blue / red line → air conditioning pressure switch (closed) → yellow / green line → heater control board → grounding. Since the condenser fan relay coil is energized, the normally open contact in the condenser fan relay is sucked, and the circuit of the condenser fan motor is turned on, at which time the fan motor starts to rotate, and the current direction is: battery positive → under the engine cover Fuse No.1, No.56 in the fuse/relay box → contacts of the condenser fan relay (closed) → blue/yellow line → condenser fan motor → black line → G201 ground. At the same time, when the air conditioner switch is turned to the ACC gear, the compressor clutch circuit can be turned on, and the air conditioner compressor starts to work. The current direction is: battery positive → fuse under fuse cover/fuse No. 41 in the relay box, No.42→White line→Ignition switch (BAT→IG2)→Yellow line→Fuse No.13 in the fuse/relay box under the dashboard of the driver's seat→Black/yellow line→Compressor clutch relay coil→Red line→ Terminal A17 of the ECM/PCM (engine/powertrain control module) → ground. In addition, when the cooling water temperature is higher than 93 °C, the radiator fan switch is automatically closed, and the coil circuit of the radiator fan relay is turned on, and the current direction is: battery positive → fuse under the hood/fuse box in the relay box. 41. No.42→White line→Ignition switch (BAT→IG2)→Yellow line→Fuse No.13→Black/yellow line→Fusel fan relay coil in the fuse/relay box under the driver's seat side panel→ Green line → radiator fan switch (closed) → black line → ground. Since the coil of the radiator fan relay is energized, the normally open contact of the radiator fan relay is brought into contact, and the circuit of the radiator fan motor is turned on, and the current direction is: positive battery → under the hood fuse/relay box Fuse No.41, No.57→Receiver fan relay contact (closed)→blue/black line→radiator fan motor→black line→grounding, make the radiator fan motor start working. 3. Troubleshooting Through the analysis of the above control process, when the air conditioning pressure switch is pressed and the cooling water temperature is higher than 93 ° C, the fan motor circuit, the air conditioner compressor circuit, the radiator fan motor circuit are all passed through the hood under the fuse/relay box. Fuse No. 41. Therefore, when checking the power supply circuit of the system, first check the fuse No.41. Spare Parts for CUMMINS Engine Spare Parts for CUMMINS Engine,Car Spare Parts ,Auto Spare Parts ,Vehicle Spare Parts Filling Machine Co., Ltd. , http://www.nbexcavator.com
Research on Circuit Analysis of Vehicle Refrigeration System
1. The power supply of the circuit is battery and generator; the control device has ignition switch, air conditioning pressure switch, radiator fan switch, ECM/PCM (engine/power system control module), radiator fan relay, condenser fan relay and compression Clutch relay, etc.; overload protection device has fuses No.41, No.42, No.54, No.56, No.57 located in the fuse/relay box under the hood, and is blown under the dashboard of the driver's seat side. Fuse No. 13 in the relay/relay box and fuse No. 13 in the fuse/relay box under the front passenger seat side dashboard; the consumer has a radiator fan motor, a condenser fan motor and a compressor clutch; Refers to a variety of monochrome lines, two-color lines and bodywork of different colors and diameters.