Check for resistance between No.2 and No.7 terminals in each switch position.
Switch
Connector
terminal
Resistance
(±1%)
Volume Down
2-7
6.81 kΩ
Volume Up
4.61 kΩ
MUTE
3.11 kΩ
Mode
2.11 kΩ
Seek Down
1.11 kΩ
Seek Up
430 Ω