Technical Heater blower only operating on high speed setting

[capers626]

Hi all,

I have a query about the heater blower on a 1993 Fiat Uno Mk2 999cc (L reg) as it is only operating on the high speed setting and intermittently when it does spring into life (three speeds available normally). It sometimes makes a whirring noise in cold weather which suggests the motor is on the way out due to age.

After doing some research, which may or may not be relevant to an Uno, it seems that when the blower fan is switched onto high speed the circuit is a straight connection from positive to negative battery power but at lower speeds electrical power is typically routed through a series of resistors or a solid state speed controller assembly that drops the voltage down, which in turn makes the blower motor turn slower.

I am not aware of a separate resistor outside the motor housing unless it is built in internally, which wouldn't make a lot of sense if it needed to be replaced? Alternatively the plastic switch control outside the casing behind the front fascia plate may have a part which does the same thing?
Is there a resistor located near to the heater casing in a more accessible location?

Can't see any mention of a resistor when looking at the layout on the Fiat ePER, unless missed.

Any thoughts or advice appreciated.

Cheers,
Andy

 

[bugsymike]

Hi all,

I have a query about the heater blower on a 1993 Fiat Uno Mk2 999cc (L reg) as it is only operating on the high speed setting and intermittently when it does spring into life (three speeds available normally). It sometimes makes a whirring noise in cold weather which suggests the motor is on the way out due to age.

After doing some research, which may or may not be relevant to an Uno, it seems that when the blower fan is switched onto high speed the circuit is a straight connection from positive to negative battery power but at lower speeds electrical power is typically routed through a series of resistors or a solid state speed controller assembly that drops the voltage down, which in turn makes the blower motor turn slower.

I am not aware of a separate resistor outside the motor housing unless it is built in internally, which wouldn't make a lot of sense if it needed to be replaced? Alternatively the plastic switch control outside the casing behind the front fascia plate may have a part which does the same thing?
Is there a resistor located near to the heater casing in a more accessible location?

Can't see any mention of a resistor when looking at the layout on the Fiat ePER, unless missed.

Any thoughts or advice appreciated.

Cheers,
Andy

May look like this and possibly on side of fan motor body.
Re slow fan and often after lack of use I have sprayed WD40 directly into fan inlet ducting and it has freed it off, OK if you can ignore the smell of WD40 for a while.