Audio System - No Reception in AM/FM/Weather Bands
Date: November 7, 2005Order No.: T-B-82.62/470
Supersedes:
Group: 82
SUBJECT:
Model 164.175/186 Model Year 2006, Up to VIN 005999
No Radio Reception in AM, FM and Weather Band
If you receive customer reports with respect to the above model vehicles of no reception while in AM/FM and weather band, there may be a short circuit in the wiring between the antenna amplifier module (A2/93A2) in the roof antenna module (A2/93) and the FM amplifier module (A2/19) in the liftgate. Perform the following troubleshooting steps to resolve.
Caution!
DO NOT replace any parts until instructed to.
A. CHECK FOR MALFUNCTIONING ANTENNA AMPLIFIER MODULE
1. Measure current and voltage at fuse 20 in rear fuse and relay panel (Figure 1). Expected current: 160- 180mA with radio on in FM mode. Expected voltage: 12V
Note:
If current is 20 - 80mA with radio on in FM mode, antenna amplifier module (A2/93a2) in antenna module (A2/93) is malfunctioning.
Caution!
Perform additional checks below before replacing the antenna module (A2/93) or the new module will be damaged!
2. Remove door lining on liftgate. See WIS document AR72.20-P-3520GZ.
3. Remove headliner. See WIS document AR68.30-P-4300GZ.
B. CHECK FOR PINK WIRE SHORTED TO GROUND
1. Disconnect red connector (Figure 2, 1) from FM rear window antenna amplifier (A2/19) (Figure 2).
2. Disconnect red connector (Figure 3, 2) from antenna amplifier module (A2/93a2) (Figure 3).
3. With an ohmmeter, measure the resistance of the pink wire to ground. See repair procedure below if the wiring harness is shorted and repair wire before performing check of amplifier.
Note:
There must be no short circuit to ground otherwise the antenna amplifier module (A2/93a2) will be damaged! Keep in mind that the liftgate moves and the short may be intermittent because of the movement! Inspection of red wire may be necessary.
C. CHECK FOR DEFECTIVE FM REAR WINDOW ANTENNA AMPLIFIER
1. With an ohmmeter, measure the resistance of the FM amplifier (A2/19) (pin 1) to ground.
2. If there is a short to ground, the FM rear window amplifier needs to be replaced.
Caution!
Perform repair procedure below for the wiring harness (D. Repair Procedure for Wiring Harness) before replacing the antenna module (A2/19) or the new FM rear window antenna amplifier will be damaged!
Note:
There must be no short circuit to ground, otherwise the FM rear window antenna amplifier (A2/19) will be damaged! Only reconnect wiring harness when instructed to!
D. REPAIR PROCEDURE FOR WIRING HARNESS
1. Detach braided ground wire (Figure 4, 3) from stud on body.
2. Unplug power connector (Figure 4, 4) and connector (Figure 4, 5) for FM2/3/WB in/from amplifier.
3. Disconnect water drain hose (Figure 4, 6) from coupling.
4. Detach grommet (Figure 4, 7) and pull wires (Figure 4, 4 and 5), ground wire (Figure 4, 3) and water drain hose (Figure 4, 6) out of grommet.
5. Remove wire harness cover (Figure 4, 8) and route wires, braided ground wire and drain hose out of liftgate opening.
6. Remove tape from wires from the connector ends to harness breakout.
7. Cut section out of pink power wire and splice in replacement wire (Figure 5, 9). Refer to WIS document AR00.19-P-0100A.
Cut specifications: Cut wire NO MORE THAN 80 mm from connector and 60mm from harness breakout.
Replacement wire specifications: 0.755 sq.mm
8. Apply tape to braided ground wire (Figure 5, 3) from harness breakout to terminal to protect the remainder of the wiring harness from being cut.
9. Re-tape wiring harness as originally installed.
10. Reinstall wire harness cover (Figure 4, 8), wires (Figure 4, 4 and Figure 5, 9), braided ground wire (Figure 5, 3), water drain hose (Figure 4, 6), and grommet (Figure 4, 7) in reverse order.
Note:
Make sure that Raychem splice connectors are not in the area where the harness bends in the grommet.
E. FOLLOWING REPAIR OF WIRING HARNESS
1. Replace antenna module (A2/93) if it was found to be defective in the above tests. Refer to WIS document AR82.62-P-8300GZ.
2. Replace FM rear window antenna amplifier (A2/19) if it was found to be defective in the above tests. Refer to WIS document AR82.62-P-8301GZ.
3. Reconnect wiring.
Parts Information
In Case of Warranty