All values measured to ground unless otherwise noted
Conn./Plug/Pin Pin Information Test Value Comments
S50      
1 Main ground to W18 Approx. 0 Ohms to ground  
2 Circuit 58d input, "Dimmed Instrum. Illumination" voltage Varies from 0.5 to 12 VDC, depending on setting of dimming value Short protected, current
decoupled from circ. 58k
3 Left outside rearview mirror in/out and up/down adjustment output Ignition on, S50 switched to left:
12 VDC to pin 7 with switch pressed to left,
voltage reversed with switch pressed to right,
12 VDC to pin 5 with switch pressed forward,
voltage reversed with switch pressed to backward
Note 1
4 Right outside rearview mirror in/out and up/down adjustment output Ignition on, S50 switched to right:
12 VDC to pin 8 with switch pressed to left,
voltage reversed with switch pressed to right,
12 VDC to pin 5 with switch pressed forward,
voltage reversed with switch pressed to backward
Note 1
5 Right and left outside rearview mirror up/down adjustment output   Note 1
See pins 3 and 4
6 Circuit 15 switched power input 12 VDC with ignition on  
7 Left outside rearview mirror in/out adjustment output   See pin 3
8 Right outside rearview mirror in/out adjustment output   See pin 4
M21/1      
1.1 Circuit 15 switched power input for mirror heating 12 VDC with ignition on Note 2
1.2 Main ground to W18 Approx. 0 Ohms to ground  
1.3 Horizontal mirror adjustment power input Ignition on, driver side selected:
12 VDC to pin 4, voltage reversed with S50 pressed left or right
 
1.4 Horizontal/vertical mirror adjustment power input   See pins 3 and 5
1.5 Vertical mirror adjustment power input    
M21/2      
1 Circuit 15 switched power input for mirror heating 12 VDC with ignition on Note 2
2 Main ground to W19 Approx. 0 Ohms to ground  
3 Vertical mirror adjustment power input Ignition on, passenger side selected:
12 VDC to pin 4, voltage reversed with S50 pressed up or down
 
4 Horizontal/vertical mirror adjustment power input   See pins 3 and 5
5 Horizontal mirror adjustment power input Ignition on, passenger side selected:
12 VDC to pin 4, voltage reversed with S50 pressed left or right
 
Note 1 Refer to D. M. Body & Accessoires Volume 3 12.5 for mirror motors and heating    
Note 2 Heater switching thresholds:
< 15° C (59° F) : heater ON
> 25° C (77° F) : heater OFF