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Discussion Starter · #1 ·
I have a Mitsubishi Carisma (1.8 petrol GLSI 1997 -5 door) and the heater fan has stopped working. Although I have the workshop manual for the car it does not contain any wiring diagrams and I was hoping someone might be able to suggest where I could get hold of this information.

Failing that suggestions as to what might be the cause of the problem would be appreciated.

I have checked the following

1. Heater resistor
2. Relays on interior fuse box (both work). The top
left hand one I believe is related to the heater and
can be felt to switch when the ignition is switched on.
3. 30A heater fuse is OK
4. I have disconnected the fan and connected it to
a 12V supply. The fan worked OK

I managed to get a copy of some Gallant wiring diagrams which I belive has many similarities with the Carisma and this was helpful as the heater wiring was much the same. As everything checked out I put 12 V on the "output" side of the 30A heater fuse socket and the fan came on and its speed control worked OK so it is clear power is not getting to the heater fan from the fuse box. I have measured the voltage on the "input" side of the heater fuse socket and it is 12V when the ignition switch is in the OFF and ACC positions. When in the ON position it drops to 6.2V which I would not expect. Surprisingly this has not blown any fuses or caused any other problems - the car runs fine as long as the windows don't mist up! The wiring on the Carisma ignition switch is different from the one shown in the Gallant wiring diagram. However, the Gallant wiring diagram does show the relay coil being energised when the ignition switch is the ON position (the power for the heater comes via the 30A fuse supply, not via the ignition switch) which is almost certainly also the case for the Carisma.

Interestingly the

1. Central locking
2. Sun roof
3. Heater
4. Clock Light

are also not working and failed at about the same time as the heater fan (almost certainly at the same time but I cannot be 100% sure).

The Gallant wiring information shows the heater being fed by Fuseable Link 1 which feeds the following:

1. Door lock Relay (15A)
2. Sun roof Relay (20A)
3. Heater Relay (30A)
5. Stop light/Cruise control (15A)
4. Clock Dome Light/Lug Comp light/Radio + other things
not on car

Of these only the radio, stop light (I assume this is the brake lights - the car has no central stop light) luggage compartment light and radio are working on the car.

I guess the next thing to do is to pull out the central locking and sunroof fuses as these relays probably switch on when the ignition is turned on and a fault in these circuits may be the cause of the problem.

Any suggestions as to what is most likely to be the cause and/or where I can get Carisma wiring digrams would be much appreciated.

Thanking you in advance


2 Posts
Discussion Starter · #2 ·
I found a wiring diagram for the Carisma which is available form

The problem when the heater, central locking and sunroof stop working together is a break in the (white) wire between the interior fuse box under the steering wheel and the fuse box under the bonnet.
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