UK Car Repair: fiat punto, vincent lake, fan switch

Question
hi
I have a fiat punto 1.6 glx 1993 with 65kilowatt. My problem is the following. The cold or hot air system is not working at all-it does not matter if i turn it to thrre or one.No cold or hot air coming through the system.We are having frost out here in germany and i hope that one of you can help me with my problem.I am tight with money and would like to try and fix it with the help of a friend-he is a bit of a handyman. Were should we start to look for the fault and is it eletrical problem?
Greetings
vincent lake

Answer
Check all fuses, wires to and from the motor and that the loom is actually connected to the fan switch on the dash (with years of switching: the spade connector can work loose)

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Since it works on NO speeds it's probably not the heater motor resistor though check this in course when checking connections (all connections should be checked for security and cleanliness + servicability (rust, burnt etc)

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The motor has one positive wire going TO it, feed 12V to the connector this wire goes to on the motor (the motor is around 100W so some decent wire ;) - if the motor spins up then focus entirely on the wiring/connectors. - if the motor is shorted internally then this will result in a big spark, please be aware of this.

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Check finally for power at the motor itself when the fan switch is on 1/2/3
A headlightbulb can be wired pretty easily for a simple tester - placed in place of the fan to test for power.

If all wires/connections are good and the motor gets power but wont turn:


The fan is under the bonnet, maybe.. never had a punto. if you can turn the fan by hand a quarter turn (with ignition OFF) (push it round with a screwdriver if access is difficult)
then try the fan. Usually one or two contacts on the commutator disconnect from the motors coil, or the brushes wear down so far they dont make contact and the3 motor can opnly start in certain positions from then on.

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Alternatively/supplemetarily

Bash (thump) the fan/airbox around a BIT with the fan turned at 1/2/3: a worn commutator/brush will turn a bit and spark a lot when bashed, so you know absolutely its a worn motor.


If it is the motor change the motor or repair the motor:

(WD40 and a bit of sandpaper can sort a dirty, toasted commutator out in an emergency and it can last around a year or so like that)

If you go this far then just search for "electric motor reconditioning"





(My car just did this exact same thing - To keep me warm I just wired the fan direct to the ignition, it works and it goes off when I stop the car)