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TEST 1 Test 1 determines if the antenna mast is insulated from the base. Proceed as follows: (1) Unplug the antenna coaxial cable connector from the radio chassis and isolate. (2) Connect one ohmmeter test lead to the tip of the antenna mast. Connect the other test lead to the (3) There should be no continuity. If continuity is found, replace the faulty or damaged antenna base TEST 2 Test 2 checks the antenna for an open circuit as follows: (1) Unplug the antenna coaxial cable connector from the radio chassis. (2) Connect one ohmmeter test lead to the tip of the antenna mast. Connect the other test lead to the (3) Continuity should exist (the ohmmeter should only register a fraction of an ohm). High or infinite TEST 3 Test 3 checks the condition of the vehicle body ground connection. This test should be performed (1) Connect one ohmmeter test lead to the vehicle fender. Connect the other test lead to the battery (2) The resistance should be less than one ohm. the braided ground strap connected to the engine and TEST 4 Test 4 checks the condition of the ground between the antenna base and the vehicle body as follows: (1) Connect one ohmmeter test lead to the vehicle fender. Connect the other test lead to the outer crimp (2) The resistance should be less then one ohm. and/or tighten the antenna base to fender mounting RADIO FREQUENCY INTERFERENCE WARNING: ON VEHICLES EQUIPPED WITH AIR- REFER TO GROUP 8M - PASSIVE RESTRAINT SYSTEMS BEFORE ATTEMPTING ANY WHEEL, STEERING COLUMN, OR INSTRUMENT PANEL COMPONENT DIAGNOSIS OR For complete circuit diagrams, see Group 8W - Wiring Diagrams. Inspect the ground paths and con- • Blower motor • Electric fuel pump • Engine-to-body ground strap • Generator • Ignition module • Radio antenna base ground • Radio receiver chassis ground wire or strap • Wiper motor. component on the vehicle (i.e., generator, blower For service and inspection of secondary ignition components, refer to the Diagnosis and Testing sec- • Distributor cap and rotor • Ignition coil • Spark plugs • Spark plug wire routing and condition. components as required. If the source of the RFI or EMI noise is identified as two-way mobile radio or telephone equipment, • Power connections should be made directly to the battery, and fused as closely to the battery as • The antenna should be mounted on the roof or toward the rear of the vehicle. Remember that mag- • The antenna cable should be fully shielded coax- ial cable, should be as short as is practical, and 8F - 6 AUDIO SYSTEMS XJ DIAGNOSIS AND TESTING (Continued) |