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 - FORM NO. 56043123 - SR 1900

SECTION 2 — KNOW YOUR MACHINE
CAB CONTROLS

Refer to Figure 2-1.

Cooling Fan Switch

2 Dome 

Light

Heater A/C Fan Switch

4 Heater 

Temperature 

Control

A/C On/Off Switch

Windshield Wiper Switch

FIGURE 2-1 – Cab Controls

Summary of Contents for 56508769

Page 1: ...SR 1900 Service Manual Cab Addendum 11 08 FORM NO 56043123 Printed in USA Models 56508769 4 cyl LPG 56508770 4 cyl Petrol 56508771 4 cyl Diesel ...

Page 2: ...lectrical Circuit Overview 13 Blower Motors 13 Condenser Fan Thermostat Pressure Switch and Compressor Motor 14 Electrical Troubleshooting 15 Symptom One or both of the Blower Motors will not run 15 Symptom The Blower Motors run but there is no cold air coming out of the Evaporator Heater Unit 16 Component Troubleshooting 17 Compressor Motor Hydraulic Valve L10 17 Accessory Gear Hydraulic Pump 17 ...

Page 3: ...ish Spanish 56041656 Operation Manual Danish Norway Swedish Finnish 56041661 Operation Manual German French Dutch Russian 56041662 Operation Manual Spanish Portuguese Italy Greek 56041663 Operation Manual Estonian Latvian Lithuanian Slovenian 56041664 Operation Manual Slovakian Czech Polish Hungarian 56041665 Operation Manual Turkish 56041666 Quick Start Troubleshooting Manual 56043110 Engine Manu...

Page 4: ...Turn the key switch off O and disconnect the battery before servicing electrical components Never work under a machine without safety blocks or stands to support the machine Do not dispense flammable cleaning agents operate the machine on or near these agents or operate in areas where flammable liquids exist CAUTION Before performing any service function carefully read all instructions pertaining ...

Page 5: ...rs Heating System 1 Fasco OEM p n 2807 510 154 Fasco p n DC136 1 8 HP 4200 RPM three speed 4 5 Amp A C System 2 SPAL type 008 A37 C 42D 4 5 Amp Refrigerant R 134a 1 3 lbs Condenser Fan Motor SPAL type VA13 AP9 C 35S 6 9 Amp Compressor ICE TM 08 HD 5 cu in 82 0 cc per revolution 700 6000 RPM Compressor Motor Sauer Danfoss p n 121 20 045 00 1 02 cu in 16 7 cc displacement Heating System Capacity 20 ...

Page 6: ... 1900 SECTION 2 KNOW YOUR MACHINE CAB CONTROLS Refer to Figure 2 1 1 Cooling Fan Switch 2 Dome Light 3 Heater A C Fan Switch 4 Heater Temperature Control 5 A C On Off Switch 6 Windshield Wiper Switch FIGURE 2 1 Cab Controls ...

Page 7: ...Refer to Figure 2 2 7 Blower Motor 8 Blower Assembly 9 Heater Core 10 Heater Air Box Assembly 11 Filter 12 Coolant Tube From Engine Radiator 13 Cab Filter Cover 14 Heater Hoses 15 Heater Control Assembly 16 HVAC Relay FIGURE 2 2 Heating System Components ...

Page 8: ...re Switch 20 A C Receiver Dryer 21 A C Compressor 22 Hydraulic Compressor Motor 23 Air Filter 24 Cab Filter Cover 25 Coolant Tube From Engine Radiator 26 Heater Hoses 27 Heater Control Assembly 28 Accessory Gear Hydraulic Pump 29 Compressor Motor Hydraulic Valve 30 Compressor Relay 31 HVAC Relay FIGURE 2 3 Air Conditioning System Components ...

Page 9: ...ty environments X 40 Clean the heater core fins and air box heater only X 160 Clean the evaporator and heater core fins inside the evaporator heater unit A C only X 160 Clean the condenser fins A C only X 40 TO CLEAN AND REPLACE THE CAB FILTER Refer to Figure 3 1 Remove the four screws holding the 1 Cab Filter Cover then remove the Cab Filter Cover and Filter from the machine Clean the 2 Filter us...

Page 10: ...y K8 The 20A circuit breaker CB9 must be closed to provide voltage RED VIO wire to the input load side of the HVAC Relay K8 HVAC Relay K8 must be closed to provide 12 VDC VIO GRAY wire to the positive terminal on the Fan Switch S30 The Fan Switch S30 must be set to the Low YEL wire Medium RED wire or High ORN wire position to provide 12 VDC to the corresponding terminal on the Blower Motor M6 Nega...

Page 11: ...er CB4 Is there voltage at each of the three positive terminals on Fan Switch S30 when the Switch is set to the corresponding fan speed YEL RED and ORN wires ref to bat neg Yes Replace the Fan Switch S30 No Replace the Blower Motor M6 The Blower Motor is not working Is there continuity in the YEL RED and ORN wires from Fan Switch S30 to the positive terminals on the Blower Motor M6 No Repair the w...

Page 12: ...back Pin 5 71 k Feedback Pin and Feedback Pot Pin 3 14 k Feedback Pot Pin and Feedback Pin 3 25 k If the 6 Feedback Pin resistance values are not close to those shown in the above table it indicates that the feedback potentiometer in the Valve Assembly is not working correctly Replace the Valve Assembly Valve Assembly Feedback Pin Feedback Pot Pin Feedback Pin Motor Pin Motor Pin Disconnect the el...

Page 13: ...ement Heater Temperature Control on the Overhead Control Plate 5 Splice the original wires from the Valve Assembly to the replacement Heater Temperature Control using butt connectors and heat shrink insulation 6 Reinstall the Overhead Control Plate in the cab 7 Yes Is there 12V to the Heater Temperature Control BLK and RED wires Is there approximately 9 75V at the Valve Assembly Connector BLK WHT ...

Page 14: ... radiator with coolant Purge the Heater Circuit Refer to Figure 4 2 Another method is to remove the hoses that run from the Valve Assembly to the heater core purge the hoses with coolant to remove as much air as possible from the heater circuit reinstall the hoses then run the machine with the heater on to purge any remaining air from the system Figure 4 2 shows the heater hose functions for refer...

Page 15: ...mally closed located on top of the A C Receiver Dryer will interrupt the 12 VDC to the Compressor Motor Hydraulic Valve L10 29 to switch off the Hydraulic Compressor Motor and A C Compressor under the following two conditions The refrigerant line pressure drops below 30 psig indicating an insufficient amount of refrigerant in the system The refrigerant line pressure rises above 270 psig indicating...

Page 16: ...must be closed to provide 12 VDC GRN wire to the input terminal on the Pressure Switch S34 The Binary Pressure Switch S34 normally closed must be closed to provide 12 VDC GRN WHT wire to the load side of the Compressor Relay K10 terminal 30 The load side of the Compressor Relay K10 normally closed must be closed to provide 12 VDC BLU BRN wire from terminal 87a to the Compressor Hydraulic Valve L10...

Page 17: ...here continuity through 20A circuit breaker CB4 Is there voltage at each of the three positive terminals on Fan Switch S30 when the Switch is set to the corresponding fan speed YEL RED and ORN wires ref to bat neg Replace the Fan Switch Replace Blower Motor M9 and or M10 One or both of the Blower Motors will not run Is there continuity in the YEL RED and ORN wires from Fan Switch S30 to positive t...

Page 18: ...GRN WHT wire on the Pressure Switch S34 ref to bat neg Is there 12V across the coil on the Compressor Hydraulic Valve L10 hopper down A C switched on There is no cold air from the Evaporator Heater Unit Yes Check replace A C Switch S35 No Check replace Thermostat S33 No Yes Yes The A C system is overheated Check the Condenser Fan Relay K9 Condenser Fan and associated wiring and replace repair as n...

Page 19: ... pressure gauge to the 1 Hydraulic Pressure Test Port off of the Accessory Hydraulic Pump Start the engine then switch the A C on and off at the two engine speeds and note the hydraulic pressures at the 2 Hydraulic Pressure Test Port The following chart shows pressure values that are representative of what you should be reading at normal operating temperature if the Accessory Hydraulic Pump Hydrau...

Page 20: ...eed to step 3 below Remove the electrical connector from the 3 Compressor Relay and check for continuity across the load terminals 30 and 87a Note The Compressor Relay is a normally closed relay and should have continuity across the load terminals with the electrical connector removed If there is continuity across load terminals 30 and 87a the Compressor Relay is working correctly Check the connec...

Page 21: ...e machine Open the rear Cover Assembly 1 Remove the electrical connector from the Binary Pressure Switch and check for continuity across the two terminals 2 Note The Binary Pressure Switch is normally closed and should have continuity across the terminals if the A C system is charged adequately and is at normal ambient temperature If there is continuity across the terminals the Binary Pressure Swi...

Page 22: ...mbient temperatures above 31 F If there is continuity across the terminals the Thermostat is working correctly If there is very high resistance or no continuity across the terminals replace the Thermostat Service Tip To verify that the thermostat is operating correctly spray electronic component cooler or canned air dusting spray onto the probe embedded in the evaporator coils to cool the probe to...

Page 23: ... TO X208 CONNECT X207 TO L5 X182 CONNECT TO TERMINAL 1 ON CB1 X182 CONNECT TO TERMINAL 1 ON CB1 1 X183 X183 L10 VALVE COMPRESSOR L10 VALVE COMPRESSOR 1 2 K8 RELAY HVAC OPTIONAL K8 RELAY HVAC OPTIONAL 86 85 87a 87 30 X189 X189 A B SP28 SP28 1 1 2 2 K10 RELAY COMPRESSOR K10 RELAY COMPRESSOR 86 85 87a 87 30 X195 X195 X190 X190 1 M M5 MOTOR ASM WIPER INCLUDES 2 SPEED SWITCH M M5 MOTOR ASM WIPER INCLUD...

Page 24: ...TIONAL S35 SW SPST S35 SW SPST 1 2 X2 X2 F F S1 SWITCH IGN S1 SWITCH IGN ACC BAT ST IGN CB3 CIRCUIT BREAKER 15 AMP CB3 CIRCUIT BREAKER 15 AMP 1 2 L10 VALVE COMPRESSOR L10 VALVE COMPRESSOR 1 2 t o S33 THERMOSTAT t o S33 THERMOSTAT 1 2 BT BATTERY 12 Vdc BT BATTERY 12 Vdc K2 K2 87a H1 HORN H1 HORN 1 2 CB5 CIRCUIT BREAKER 10 AMP CB5 CIRCUIT BREAKER 10 AMP 1 2 M M10 MOTOR BLOWER MOTOR M M10 MOTOR BLOWE...

Page 25: ...STEM PLUMBING AND HYDRAULIC FLOW SCHEMATIC Heater Core 1 AC Evaporator 2 Radiator Coolant Tube 3 Feed Hot Water 4 Return Flow 5 Heater Control Valve 6 Hydraulic Test Port 7 Low Pressure Refrigerant Gas 8 High Pressure Gas 9 High Pressure Liquid 10 ...

Page 26: ...Nilfisk Advance A S Sognevej 25 DK 2605 Brøndby Denmark Tel 45 43 23 81 00 Fax 45 43 43 77 00 www nilfisk advance com ...

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