Antenna Cable - Routing

87mitsubishi02

SUBJECT:

TRUCK ANTENNA CABLE ROUTING
NO. STB-87-08-011

DATE August, 1987

MODEL 1987 Truck
NOTE: THIS BULLETIN REPLACES THE PREVIOUSLY ISSUED "TRUCK ANTENNA CABLE ROUTING" BULLETIN (STB NUMBER STB-87-08-07, DATED APRIL, 1987) DUE TO AN INCORRECT STB NUMBER. DISCARD THE ORIGINAL BULLETIN. HOWEVER, DO NOT DISCARD THE CORRECTLY NUMBERED STB-87-08-007, TITLED "PRECIS WIRING CHANGE".

PURPOSE

In early 1987 model PB trucks, poor radio reception may be caused by a short or open circuit in the antenna lead-in cable. This bulletin describes the ;fcondition and the corrective action.

FIGURE 1:

FIGURE 2:

DESCRIPTION

The antenna lead-in cable is routed across the passenger-side toe board as illustrated in Fig. 1. In early-production 1987 models, the cable was clipped directly to the floor panel as shown in Fig.
2. Here, exhaust heat could damage the insulation. causing a short or open circuit.

FIGURE 3:

FIGURE 4:

In October, 1986 production, the cable was rerouted as shown in Fig. 3 so that the silencer pad insulated it from heat. Later, the cable was sheathed in a tube and again routed under the silencer pad as in Fig. 4 on Page 2 of this bulletin.

FIGURE 5:

CORRECTIVE PROCEDURE

1. Check the continuity of the antenna cable by connecting an ohmmeter between the antenna mast and ground (Fig. 5). If there is continuity, the cable core and shield are shorted.
2. Connect a known good antenna to the radio. If reception improves, replace the original antenna.

NOTE: To connect the cable to a full audio system, remove the system to connect the cable. In other cases, remove the glove box to reach the antenna cable connection.

FIGURE 4:

FIGURE 6:

3. Route the new antenna cable under the carpet but over the silencer pad as shown in Fig. 6 and secure it with tape. However, if the new antenna comes with a corrugated tube, route the cable under the silencer pad as in Fig. 4 and secure with existing metal clips.
WARRANTY INFORMATION

Normal warranty procedures apply.