Antenna: Testing and Inspection
CHECKING RADIO CABLES, ANTENNA GROUND G3O5 AND SLOT ANTENNACheck Radio reception or Radio noise in an area away from tall buildings, metal structures, power lines, fluorescent lighting and power tools. Tune to high and low ends of the dial on both AM and FM, checking weak and strong station reception.
CHECKING RADIO CABLES
The following cables should have the following approximate resistance values when measured at each end:
CABLE APPROX TYPICAL VALUE
Lead-in (between back of Radio and ECM bracket) Inner Conductor 0.8 to 1.2 ohms. Outer Conductor 0.2 to 0.3 ohms.
Intermediate (between ECM bracket and roof rail) Inner Conductor 0.8 to 1.2 ohms. Outer Conductor 0.2 to 0.3 ohms.
Resistance measured between the inner and outer conductor of the lead-in or intermediate cable should be infinity ("OL" on most DVOMs).
ANTENNA WIGGLE TEST
When checking resistance, cautiously wiggle the cable. The above readings should always be obtained. If not, some portion of the cable is intermittent and should be replaced.
CHECKING ANTENNA GROUND G305
^ G305 ground screw should be the "shiny" type.
^ Use a DVOM to measure resistance between ground G305 and a good chassis ground. Resistance should be 0.5 ohms or less.
CHECKING SLOT ANTENNA
If the values listed in the "Checking Radio Cables" and "Checking Antenna Ground G305" are correct, check for:
^ Short to ground of the inner conductor of the integrated roof antenna lead-in cable.
^ Resistance measured between the inner and outer conductor of the integrated roof antenna lead-in cable should be infinity ("OL" on most DVOMs).
^ Torn or folded integrated roof antenna.