Making switch
There are two switches, 4x4 electronic clutch power switch and 4x4 computer reset switch (as option you can
make third switch which will turn on/off 4x4 orange warning light on instrument panel by cutting and inserting
additional switch to amber-black wire which is first wire on G270a connector). There are two ways of doing
4x4 electronic switch one is to cut ZN (purple black) or S (pink) wire on I76 relay but since you need to open
central console to make 4x4 computer reset switch I’ll describe second way which include cutting (purple
black) ZN wire which is #3 wire on G270a connector. Electronic scheme you can see page or two down,
you’ll need 2 switches (20A or more preferred) one is for 4x4 switch and it is normal switch (if you can find
original Alfa Romeo switch like for fog lights/all 4 direction lights/rear window defogger) other switch 4x4
reset switch should be momentary switch (like reset switch on computer) but normal will work also only you’ll
have step more to do, 6-7 meters/yards of 2,5mm
2
car wire, flat and cross screwdrivers, scalper or similar
sharp object with which you’ll cut wire and strip it (take off plastic/rubber electric insulation ), electric
insulator tape (or any electric insulator spray) .
First you have to decide where in cabin would you like to have those switches, best place for them would be on
lowest part of central console, between hand brake and ash tray since it’s closest of connector and less wire we
have, less resistance (ohms) we insert to 4x4 system, second best place for it would be on drivers shelf between
steering wheel and central console, last place should be between steering wheel and driver door (this is not
desirable location as you need long wires to reach that location but to me it is most ergonomic and esthetic
place) , so you need to sit little in drivers seat and move hands around and see which location suits you best I
recommend first as it’s closest to connector.
0. take screwdriver and unscrew drivers (4 upper,2 lower screws) and co drivers shelves (2-3upper, 2
lower screws)/ if you can reach G270a connector behind ash tray and shelf above it by removing those
two go to step 4. but I couldn’t
1. take flat screwdriver and take out air ventilation mask and all three ventilation tunnels behind it on
central console, take it out
2. take flat screwdriver and open plastic cap to access cross screw on rear part of central plastic which
protects handbrake it is just after rear ash tray at rear seats, take it out
3. take off leather/plastic thing around gearshift knob, unscrew two screws that are behind ventilation
system at upper part of central console, also unscrew two screws holding it in middle, and at last
unscrew last one near handbrake (maybe you’ll need to loosen an bit plastic L pieces around central
console, so you may need Super ATTAK or any other glue when putting it back on)
4. find G270a and G270b connectors and locate wire #6 SN (pink-black) or S (pink) depending which
side of G270a connector you’re looking at, strip wire and cut it after that connect both new ends of SN
wire to 4x4 reset switch with 2.5mm2 car wires, insulate with tape all connections
5. locate wire #3 ZN (purple-black) of G270a connector, strip wire and cut it after that connect both new
ends of ZN wire to 4x4 switch with 2.5mm2 car wires, insulate with tape all connections
6. make holes and install switches on central console or wherever you decided to put them
7. start car and test both switches, when you press 4x4 switch it should disengage el. Coupling which will
result click noise followed by lighting up 4x4 warning light depress switch and you’ll see that nothing
happens, yellow light is still on because until you reset 4x4 computer it wont try to reengage coupling,
after you press 4x4 reset switch, yellow lights will turn off you’ll hear click noise which is el. Coupling
engaging and if all is OK yellow light will stay off, now press foot brake pedal to see if system is OK if
each time you press brake pedal hear clicking sound from el. Coupling then yours system has too much
wire and to high resistance is added to 4x4 system (unless yours car did that before you installed switch
in which case you do not need to worry, my didn’t) and computer each time you press brake pedal
calculates (what computer uses to calculate 0.2G I still don’t known, I can only guess) that we have
excided 0.2 G force limit in braking and it disengages drive shaft it isn’t that bad if rear brake pressure
valve is working OK but it would be better that we don’t have this side effect. Take car for spin to see if
it acts as before with 4x4 engaged.
8. If all is OK and yellow light don’t come after some time of driving and braking, screw back all parts of
console and shelves.
9. CONGRATULATIONS ON SUCCESSFULLY INSTALLING 4X4 SWITCH
On following page 30 (298 page of wiring diagram) you can see electric wiring scheme of both switches installed on one side of
G270a connector of 4x4 system, but you can also install it on other side of that connector which leads to 4x4 computer at end of
car N50 page 31 (seen on page 297 of wiring diagram).
