Audi A4

since 1994 release

Repair and operation of the car

The antenna on back glass

As the antenna for reception of average waves in this type of antennas three metal conducting paths in the top of glass are used.

For reception of VHF other conducting paths which at the same time serve as heating elements serve. Insufficient height of this system of antennas is compensated by the amplifier under the left back facing of a rack of a roof.

Search of malfunctions in the antenna of back glass

Back facing of a rack of a roof can be removed, having shown a great patience and dexterity, in cars with the leaning-back back of a back seat without other dismantling works. But in cars with a rigid back not to do without its dismantle. In general work is facilitated after dismantle of a back reception pocket and lateral facing of the leaning-back seat (the head Salon).

PERFORMANCE ORDER

Remove both facings of racks of a roof behind.
Check connection with the mass of heating of back glass on the right rack of a roof, and also, whether the amplifier of the antenna fixing screws is reliably connected to weight.
Attentively check the top three conducting paths on back glass: whether there is a visible gap? If yes, carry out repair by a conducting silver varnish or put new back glass.
Now electric check follows: Disconnect the socket of a thin white tokopodvodyashchy wire above on the amplifier, measure tension concerning weight. For this purpose turn on the radio receiver.
Existence tension from the accumulator: giving of current on the amplifier as it should be. There is no tension: eliminate a gap in a wire.
On the same wire measure current between the socket of the amplifier and the removed wire.
The ampermeter has to show 30–50 ma, otherwise the amplifier of the antenna does not consume current and, therefore, it is faulty – replace.
Following check: disconnect the lower wire on the warmed back glass, include ignition and heating of back glass, measure tension in a wire.
In it there has to be accumulator tension, otherwise malfunction in a tokopodvodyashchy wire or in the amplifier, outline damage.
Disconnect lower (thick white) a wire on the amplifier, measure tension at the included ignition and heating of back glass:
If there is accumulator tension, a tokopodvodyashchy wire as it should be, possibly, the amplifier is faulty. If is not present, then on the contrary.

Loudspeakers in facing of a forward door

The loudspeaker of average frequencies located below is also screwed behind on facing of a door. Figures from "1" to "3" designated fixing screws.

PERFORMANCE ORDER

Dismantle facing of a forward door.
Carefully remove the damping film which is behind facing of a door from polyfoam.
Disconnect the wire socket in a connecting wire from lower to the top loudspeaker.
Loudspeaker of average frequencies: weaken three fixing screws of the loudspeaker and take out directing wires.
Loudspeaker of high frequencies: weaken the screw with a crosswise head behind on dynamics, remove the loudspeaker.

Back loudspeaker

The back loudspeaker is screwed from above on body metal under a reception pocket (arrow). That to dismantle it, it is necessary to remove a back reception pocket in the beginning.

PERFORMANCE ORDER

Dismantle a back reception pocket (the head Salon).
Weaken screws with crosswise heads, remove the loudspeaker.