Correct Testing of Sensing Switches{7400,7402,7422}
Usage:
Reference: Service Magazine; June 23, 1986; Page 6; "Hydraulic And Coolant Flow Switches in Electronic Monitoring System Can Be Damaged By Incorrect Testing."
When testing sensing switches such as pressure, temperature, flow level and other switches that provide input to monitor panels (EMS, CMS, Excavator Monitor), use only a 6V7800 or 6V7070 Digital Multimeter. This also applies to backup alarm switches too. The use of continuity testers like an 8T0500 or an analog type multimeter can cause a momentary surge of current that may damage these switches. Continuity testers should only be used when testing harnesses, fuses, and circuit breakers for open circuits.
Caterpillar Information System:
1991/05/20 New Speed Setting Clutch Group For 3161 Woodward Governors{1265}
1991/05/20 Two Scavenge Screens Now Used In Scavenge Oil Pumps{1312}
1991/05/20 Replace Camshaft And Install New Lifters If Pitting, Spalling, Or Wear Occurs On Lobes Of 4N0599 And 4N0602 Camshafts In Fuel Injection Pump Groups{1251,1253}
1991/05/20 Procedure To Retain Oil Pump When Pump Mounting Pad On Cylinder Block Is Broken{1201,1304}
1991/05/20 Cylinder Kits Not Recommended For Use In 3400 Family of Marine Engines And D8N Tractors{1214}
1991/05/20 Do Not Weld Repair Worn Wheel Spindles For Off-Highway Trucks Or Wheel Tractor-Scrapers{4002,4205,4234}
1991/05/13 Unwanted Engine Shutdown Caused By "01" And/Or "04" Diagnostic; New "09" Diagnostic Available With 8T9881-8 Electronic Control Module (ECM){4490}
1991/05/13 Engine Updates Help Prevent Piston Seizures{1214,1252,1265,1274,1355,1383,1393,1456}
1991/05/13 Rear Gear (Cam Drive) Groups Improved{1206,1201,1212,7551,7552,7553}
1991/05/13 New Specification For Exhaust Valve Clearance{1123,1121,1105}
1991/05/13 Replacing A 3176...(2YG) Truck Engine With A 1991 3176...(7LG) Truck Engine{1000,1119,1408,1901}
1991/05/13 Component Changes For 1991 Model 3176 (7LGH, 43Z) Engines{1052,1087,1119,1215,1290,1292,1304,1361,1362,1378,1408,1901,1902,1912}
1991/05/27 Expected Future Air Conditioning Service Requirements{7320,1802}
1991/05/27 Technical Marketing Information (TMI) System for Commercial Engine Products{0337,0334,0336}
1991/05/27 Smaller Connecting Rod Bolt Used In 4W6425 Air Compressor; Use Correct Torque{1803}
1991/05/27 New Fuel Manifolds And Clamps Reduce Vibration Of Fuel Lines{1252,1702}
1991/06/03 New Deutsch HD-10® Electrical Connectors Used{1400,1408}
1991/06/03 Reference Emissions Graph Helps Determine Oxides Of Nitrogen{1050}
1991/06/03 New Oil Drain Assembly Used; Be Sure To Correctly Tighten Drain Plugs, Port Plugs, And Pipe Plugs In Oil Pans{1302}
1991/06/10 New Timing Specifications For 3500 Spark-Ignited Engines{1552}
1991/06/10 1,1,1-Trichloroethane May Damage Deutsch C-E Electrical Connectors{1400,0645,0785,1450,1550,1900,3168,3225,3418,4294,4323,4450,5485,5700,7400,7450}
1991/06/17 New Three-Ring Pistons And New Rings Used In New Piston And Rod Groups To Provide Improved Oil Control{1214,1215}
1991/06/17 New Seal And Improved Plate Eliminate Leaks In BrakeSaver Water Lines Group{1380,1155}
1991/06/17 Personality Modules For 1991{1902}