Have you checked that there is power going to the head unit with a multi meter
This is what the RAVE disc says
High-Line In-Car Entertainment Description
The high-line in-car entertainment system consists of a radio cassette player,
located in the centre of the fascia, a power amplifier located under the LH front
seat and a CD autochanger located under the RH front seat. Radio headphone
amplifiers are located in the lower rear quarter trim casing. Remote radio
controls are located on the LH side of the steering wheel. The high line system
has:
A high range speaker located in each A post trim
A low and mid-range speaker located in the front doors
A low and a high range speaker located in the rear doors
Low range speakers located in a housing on the tail door
An AM/FM antenna mounted on the RH rear side window and an FM
antenna mounted on the LH side window. The LH antenna is used for
improved FM reception in urban areas.
The system can be controlled from the radio cassette player, the remote radio
controls on the steering wheel, or the radio headphone amplifiers. The drivers
selection via the radio cassette or radio remote controls has priority over the
radio headphone amplifiers control selections.
In-Car Entertainment (ICE) High-Line System Supply
Circuit supply
A permanent feed from the battery positive terminal is connected by an R wire
to the engine compartment fusebox, where it passes through fusible link 3.
From fusible link 3 the feed passes on an NR wire to fuse 20 in the passenger
compartment fusebox. From fuse 20 the feed flows on a P wire via header
C0725 to the radio cassette player. This feed supplies power to the internal
memory and the power switch on the radio cassette player.
A feed for illumination passes through fusible link 13 in the engine
compartment fusebox and on an NG wire to the lighting switch. From the
lighting switch the feed passes on an R wire to fuse 33 in the passenger
compartment fusebox. The feed from fuse 33 is connected to header C0759 by
an RO wire. From header C0759 the feed is connected via splice joint A56 to
the radio cassette player on an RN wire.
The permanent feed to the engine compartment fusebox is also connected in
series through fusible links 1 and 7. From fusible link 7 the feed is connected to
the contacts of the auxiliary circuits relay.
A permanent feed from fusible link 7 in the engine compartment fusebox is
connected to fuse 17 in the passenger compartment fusebox on a PG wire.
From fuse 17 the feed is connected to the power amplifier by a LGP wire.
NOTE: This feed is operational when enabled by a signal from the
radio cassette player.
Another connection inside the engine compartment fusebox connects fusible
link 8 to the permanent supply. From fusible link 8 the feed is connected to the
passenger compartment fusebox on an NW wire. From the passenger
compartment fusebox the feed flows to the ignition switch on an N wire.
Ignition switch supply
When the ignition switch is in position II, the feed from fusible link 8 in the
engine compartment fusebox flows on an LGW wire to fuse 26 in the
passenger compartment fusebox.
From fuse 26 the feed is connected on an LG wire to the coil of the auxiliary
circuits relay. The coil of the auxiliary circuits relay is earthed via header
C0286 LHD/C0288 RHD to earth header C0018 on a B wire.
When the ignition switch is in position II the coil of the auxiliary relay is
energised closing the relay contacts.
The feed from the contacts of the auxiliary relay flows on a WG wire to fuse 16
in the passenger compartment fusebox. From fuse 16 a feed on an LGO wire
flows to header C0296. From header C0296 the feed flows on a LGO wire to
the LH and RH radio headphone amplifiers.
NOTE: This feed is operational when enabled by a signal from the
radio cassette player.
Another feed from fuse 16 in the passenger compartment fusebox is connected
via splice joint A7 to the radio cassette player on an LGP wire. This feed
supplies the power to the radio cassette on/off switch and glowring illumination.
A feed from the radio cassette player is connected via header C0285 LHD/
C0761 RHD and header C0296 to the LH and RH aerial amplifiers, and the LH
and RH radio headphone amplifiers on RU wires.
NOTE: This feed is the power supply to the aerial amplifiers and
forms the system enable output from the radio cassette player to
the radio headphone amplifiers and the power amplifier. This feed
is on as long as the radio cassette player is switched on.