Audio - Poor FM Reception, 1 or Both Channels Fade
Number: 92-287-9ASection: 9A
Date: SEPT. 1992
Corporate Bulletin No.: 239009
ASE No.: A6
Subject:
POOR FM RADIO PERFORMANCE WITH COMMUNICATION DATA MODULE (CDM) RECEIVE BOXES
Model and Year:
1992 ALL PASSENGER CARS EXCEPT GEO 1992 C/K, S/T, M/L, R/V AND P TRUCKS 1992 LUMINA APV
Condition:
Some 1992 vehicles equipped with a CDM (Communication Data Module) receiver box may exhibit one or more of the following conditions on FM stations: both channels fade, right channel fades, loss of volume, radio switching from stereo to mono, or treble cuffing out.
Correction:
For 1992 vehicles with any of the symptoms listed above, verify that the receiver box is both a CDM and a 1992 model radio.
There are two ways that CDM receivers are mounted: a remote mounted receiver box, and a receiver box integral with the radio control head.
1. Remote Mounted Receiver Box - this type of radio has the box mounted in a different location from the control head. All these receiver boxes are CDM.
Remove the receiver box to locate the bar code serial number label, shown in Figure 2. A large "2" means that the unit is a 1992 model. If the serial number begins with a "3" or "4", the receiver box should be sent in for service to an authorized AC Delco service center. If the serial number begins with "5", the latest changes have been made internally, and other causes for the conditions should be investigated.
2. Integral Receiver Radio - Remove the radio to determine if it is a CDM unit. This type of radio is a two piece unit with the receiver box bolted to the control head to form one unit, as shown in Figure 1.
Locate the bar code serial number label, shown in Figure 2. A large "2" means that the unit is a 1992 model. If it is a 1992 unit, return the integral receiver radio to an authorized AC Delco service center.
Warranty Information:
Use labor operation R0750, with appropriate time.