Találtam egy kis okosságot az elektromos segédfűtésről. Igaz kicsit bírni kell hozzá az angol nyelvet:
The PTC heaters were an optional component for 'cold weather' regions. I
don't think the USA got them, but Canada did. I know the UK didn't - we also
didn't get heated mirrors on Gen 2, while left-hand-drive cars in Europe
did, I think because they had one specification for all of continental
Europe.
I think the relays are only fitted on cars where the heater is fitted. The
PTC relays are in the engine room relay box, which is behind the engine
itself, just below the wipers. Counting from left to right, the PTC relays
are number three and four, marked PTC HTR 1 and PTC HTR 2.
In the main fuse box, where the jump start terminal is (driver's side of the
engine bay) there are two fuses marked PTC HTR 1 and PTC HTR 2. You should
check that the two fuses (rated 30A) are fitted, if the PTC heater is
present, and that they are unbroken. They're towards the top of the box in
the left-hand column as you stand in front of the car.
These two fuses and relays supply current to the two electric heater
elements in the heater core. There's also a heater element somewhere in the
footwell air duct in the centre of the car - it's not clear whether this is
the front or rear footwells. This is controlled by the 50A PS HTR fuse and
PS HTR relay (furthest left in the engine room relay box). The three heating
elements should operate independently since they have different power
supplies.
These are the conditions under which the electric heaters operate:
- Car in READY, blower motor ON, i.e. not in AUTO, where - except when
defrosting - the blower doesn't start until sufficient engine coolant
temperature is reached.
Heater core PTCs:
- Air directed to foot, foot/defrost (windscreen), or defrost (windscreen)
- Engine coolant temperature below specified temperature
- Ambient temperature below specified temperature (if in defrost mode)
- 'Air mix damper' opening angle is above specified value
Footwell heater:
- In foot or foot/defrost mode
- Engine coolant temperature below specified temperature
- 'Air mix damper' opening angle above specified value
The 'air mix damper' part is confusing. I think it's a pair of blades which
govern whether air is sent to, or bypasses, the heater core. The control
part describes three positions, all, half, or none going to the heater core;
this may be continuously variable, however. The service manual says that the
PTC heaters only operate with this set to MAX HOT, but I don't think it
means that you have to set the temperature to MAX HOT, just that all the air
would be going to the heater core.
The electric heaters are turned off if the car's electrical load is high, so
they may not work if the headlights are on.
With the coolant thermos fitted (standard in USA and Canada), I imagine that
the car will effectively dump the stored coolant into the heater core, then
only once that's cooled down below the desired temperature will it turn on
the PTC heater elements.
