The 7622 has full controls on the separator itself but has an option for a remote lighted switch that can be mounted elsewhere. The switch option is redundant unless you actually like to see what state the separator is set to. My separator is under the bench seat and access is difficult so I ordered the remote switch.
__________________
2006 Ford 6.0PSD EB-50/E-PH SMB 4X4 Rock Crawler Trailer
It's one part. The separator (actually a magnetic latch relay) houses all the electronics it uses to operate. Depending on how you connect it determines how it operates. There are a few optional parts you can purchase such as the remote switch.
__________________
2006 Ford 6.0PSD EB-50/E-PH SMB 4X4 Rock Crawler Trailer
Hum, maybe they changed from what I ordered back in the day. Seems the remote switch is now included with the 7622 whether or not you want it? I'm pretty sure I paid for the separator and later the remote but I could be wrong. It was several years ago. Sorry for the confusion.
__________________
2006 Ford 6.0PSD EB-50/E-PH SMB 4X4 Rock Crawler Trailer