Porsche 928 1979 Owner's Manual page 61

Fuses and relays
A failure in the electrical system may be
caused by a burned fuse or a faulty relay.
The central fuse/relay board is located
the passenger's footwell and protected by
a cover plate.
The relay board holds a row of 34 fuses
along the top edge, numbered 1 through 34.
Underneath are two rows of relays, identi-
fied with Roman numerals l-XXII.
Before replacing a fuse, turn off all elec-
trical components and the ignition; remove
the key. Replacing a fuse or a relay with the
60
engine running or the
cause electrical shock.
A burned fuse indicates an overload in the
circuit. W h e n a fuse is blown, it is not suf-
ficient to merely replace it. The cause of the
short circuit or overload must be located.
Fuses should never be patched up with tin
foil or wire as this may cause serious dam-
age elsewhere in the electrical circuit.
To replace a fuse . . .
1 - lift carpet in the passenger's footwell and
remove protective cover plate from fuse/
relay board
2 - t u r n fuses between contact springs until
metal fuse strip faces upward. In a blown
fuse the metal strip is separated
in
3 - take out blown fuse
pressing the upper contact spring
4 - carefully install new fuse so that the me-
tal strip is visible. The fuse must fit
tightly between the contact springs - do
not bend the contact springs
5 - replace cover plate and carpeting.
It is advisable to always carry a few spare
fuses in the car.
Relays
ignition on could
I & II
III
IV
V
VI
VII
VIII
IX
X
XI
XII
XIII
XIV
XV
XVI
XVII
XVIII
XIX
XX
by carefully de-
XXI
XXII
To preclude any possibility of damage, we
recommend you have a faulty relay checked
and exchanged by your authorized Porsche
dealer.
- rear w i n d o w defogger
- headlight motor control relay
- main power supply relay
(headlights)
- turn signal flasher unit
- power w i n d o w controls
- headlight washer pump
- not connected
- time relay for seat belts
- two-tone horn
- AC compressor
- fog lights
- headlight beam power supply
relay (on/off)
- high/low beam relay
- bridge (starter relay)
- safety relay for headlights
- fuel pump
- extra cooling fan for AC
- intermittent wiper relay
- intensive washer system pump
- heating and AC blower switch
- defroster