{-
-- the following executes the script and does what I want:
-- cd /home/username/scripts
-- ./syncl.sh
--
-- I'm attempting to run the service with:
-- systemctl start syncl
-- but I get an error, and unfortunately not a very descriptive one
-}

-- error via systemctl status syncl.service

● syncl.service
   Loaded: loaded (/etc/systemd/system/syncl.service; enabled; vendor preset: enabled)
   Active: failed (Result: exit-code) since Wed 2019-03-27 00:46:53 MDT; 6min ago
  Process: 7680 ExecStart=/home/username/scripts/syncl.sh (code=exited, status=1/FAILURE)
 Main PID: 7680 (code=exited, status=1/FAILURE)

Mar 27 00:46:53 computername systemd[1]: Starting syncl.service...
Mar 27 00:46:53 computername syncl.sh[7680]: Failed to connect to X Server.
Mar 27 00:46:53 computername systemd[1]: syncl.service: Main process exited, code=exited, status
Mar 27 00:46:53 computername systemd[1]: syncl.service: Failed with result 'exit-code'.
Mar 27 00:46:53 computername systemd[1]: Failed to start syncl.service.

-- contents of /etc/systemd/syncl.service

[Service]
Type=oneshot
RemainAfterExit=yes
ExecStart=/home/username/scripts/syncl.sh

[Install]
WantedBy=multi-user.target

-- contents of /home/username/scripts/syncl.sh

#!/bin/sh -e
synclient TouchpadOff=1