heater blower not working[ [another one]
You can have 12 or 13 volts, but hardly any amps.
I don't know how much a heater motor draws, but I would guess it's around 10amps at 12 volts, maybe 15.
Have you checked the fuses, to make sure there not just not blown, but the are the correct amperage?
Also, run a positive wire to the feed spade and a negative wire to the earth connection of the motor from a known source, like the battery, to make sure all is well with the motor. (could set the whole lot up on a bench with switch and resisistor first)
You may just have a burnt out wire, poor connection or a broken cable. Could even be a poor connection the fuse board.
If the amps are low, it won't work. Imagine if the starter motor wire had a 5 amp wire running to it. It would have 12 volts, but not enough of that 12volts to turn the starter. Its the difference between flow and pressure, like turning on a tap, if there's plenty of flow, but not enough pressure, the bath takes longer to fill.
Have you got an Ammeter on your multi meter?
Also, you can try the feed wires to the motor on a bulb, to see if it lights and how bright it gets, as a rough indicator.
Have you checked the resistances on the heater rheostat?
I have some info already, but first I need to know what year your car is, then we can get the correct wiring diagram, and I can use that to explain how and what to test.
UPDATE…So far I've found 3 different systems of wiring with the 3 position switch type, so if you could give me the model year, I can get to work on a guide.
Just as a matter of interest, 2 of the diagrams show the glove box light taking the feed from the same place as the heater fan motor (S14, 20amp). Does yours have a glove box light? and if so does it work?
Last edit: by Longimanus
Mine's overheating the switch, so I guess I will be replacing the resistor or motor soon to!