Porsche 996 TT Repair Manual page 1792

2 Connect the other end of the improvised
lead connection at the connection for
terminals 30, 15 to the fuse of the radio or
the amplifier.
Interference noise still present?
3 Check whether the noise occurs when a
switch or an accessory component is
switched on.
4 Briefly disconnect the connections on the
alternator and start the engine.
Noise still present?
5
8. Find out which circuit is causing the
interference noises by removing
individual fuses, relays and switches.
9. Insert all removed fuses, relays and
switches again.
10. Disconnect all components in turn
which are connected to the affected
circuit, until the interference noise
has disappeared.
11. Replace defective components.
Noise still present?
6
12. Lay all wiring harnesses from
the defective component and
the connecting leads with
suitable clearance.
Interference noises due to power supply
einordnung
Lay terminals 30, 15 and the
ground lead differently or insert a
new lead and lay the new lead at a
diastance from all other current
circuits.
Noise still present: ' Step 3
Noise no longer present: ' End
Localise the cause for the
interference noise in the retrofitted
accessories and remedy
' End
=> Interference noises due to
alternator
' Step 6
' Step 7
7. Connect the
other end of
this lead to the
vehicle
battery.
If the noise is still
present, the
amplifier is the
cause of the fault '
Step 2
Noise no longer
present ' Step 3
' Step 3
The noise occurs
when the engine is
running
' Step 4
The noise occurs
with the ignition
switched on and
the engine at
standstill
' Step 5
=> Interference
noises due to
engine
' End
' End
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