2002 Punto, 8V 1.2

Heater fan isn't working on speeds 1 & 2.
Speeds 3 & 4 do work.

Have tested the fan switch with my multimeter and all four position are working (meter reading zero).

How do I test the resistor unit?

I sprayed the plug/socket with electrical cleaner but no go for speeds 1 & 2.

Whats the condition of the connector?
Usually they fail on all speeds...
Whats the colour of the wiring like?

When all connected up - does wiggling make the fans suddenly come to life?

Ziggy

I reconnected and tried the wires but no speed 1 or 2.

All looks well, no burning or loose wires.

Thermal link is intact according to my multimeter.

A seller on ebay has is selling new at £13. I asked them and they reckon if I've got speeds 3 & 4 but not 1 & 2, and the switch is good on all 4 speeds, then is a resistor unit fault.

Time to fork out £13 I suppose!

Yes try a new one and if it doesn't work send it back for refund.
Post results of what happens please.

Fault identified, it is the resistor unit.

I found the Haynes for the car and look at the wiring schematic.

T4 (speed 4) - black/grey wire.
T3 (speed 3) blue/red wire
T2 (speed 2) green/black wire
T1 (speed 4) grey wire

T4 connected directly to motor
T3 connect to T4 via x1 resistor
T2 connect to T4 via x2 resistor
T1 connect to T4 via x3 resistor

Mine has a break between T1/T2 and T3, hence no lower speeds

unusual one though

Very unusual

Not the usual failure way at all...
Ive had speed 3 fail on and off due to damaged wiring

Id wack a scrappy unit in tbh, i dont know how good the cheap chinese versions are...

Ziggy

I'll take my chances with the new one. The seller claims they've not had any bother with them.

For anyone needing a Punto heater resistor unit, here.

if there willing to put 3 year warrenty on it - its gotta be worth a shot tbh

Ziggy

The new unit is installed and the fan has all four speeds working - job done!

The easy way to test the resistor unit is to test between pin 4 and all the other pins.


Thanks for the reply postings Gents.

Well done and good work.