Optimus 120-2154 - Manual (Page 10)

Make sure you have securely made all other connections, then plug the
harness' connector into the stereo's 14-pin wiring socket. Reconnect the
cable to the vehicle's negative (-) battery terminal.
TESTING THE CONNECTIONS
Turn on your vehicle's ignition and install your stereo's control panel
(see "Installing the Control Panel" in Faxback Doc. # 48530), ON/OFF
lights. Then press ON/OFF. The stereo's buttons and display light.
If the stereo does not work, immediately disconnect the cable from your
vehicle's negative (-) battery terminal. Then recheck your connections.
After you verify that the button/display light, follow the instructions
in "Mounting the Stereo" below.
CAUTION: If you played a CD while testing the connections, be sure to
remove the CD from the stereo before continuing.
MOUNTING THE STEREO
Be sure you verify that the stereo is connected properly (see "Testing the
Connections" above). Then follow these steps to mount the stereo.
1. Make sure the ignition is turned off, then disconnect the cable from
your vehicle's negative (-) battery terminal.
2. Disconnect the wire harness and the antenna.
3. Press RLS on the right side of the control panel to remove the control
panel.
4. Remove the tape that holds the sleeve in place and slide the sleeve
off of the stereo.
Note: If you have a Cat. No. 12-2154 stereo, you have already removed
the tape (while setting 2CH/4CH). Continue with Step 5.
5. Turn the sleeve around so the flat tabs on the front are facing you,
then insert it into the dash. Then secure the sleeve to the dash by
bending out the tabs with a screwdriver. Bend out all the side tabs.
6. If your vehicle has an existing mounting hole behind the dash, use
pliers or a 5/16-inch box end wrench to attach the short end of the
supplied mounting bolt to the back of the stereo.