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dan9090

Heater blower motor not working

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Hi, My blower motor has stopped working (even on high speed without using resistor). Having read all the past posts on this I have checked:

duct and drain hole in woing - was full of 1" of muck and as hard as concrete but now all cleared

electrical connections - seem fine, have cleaned and WD40'd

mechanical levers - both seem to be operating the levers on the heater box absolutely fine

I have checked whether I can spin the fan using my hand in the wing. I can but I certainly wouldnt call it "free" (eg: its not like spinning a bicycle wheel upside down) however I wouldnt call it "stiff" either, could move fairly easily with a couple of fingers.

Judging by this do you think I have a knackered motor or does motor sound ok??

Thanks, Dan

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Hi, My blower motor has stopped working (even on high speed without using resistor). Having read all the past posts on this I have checked:

duct and drain hole in woing - was full of 1" of muck and as hard as concrete but now all cleared

electrical connections - seem fine, have cleaned and WD40'd

mechanical levers - both seem to be operating the levers on the heater box absolutely fine

I have checked whether I can spin the fan using my hand in the wing. I can but I certainly wouldnt call it "free" (eg: its not like spinning a bicycle wheel upside down) however I wouldnt call it "stiff" either, could move fairly easily with a couple of fingers.

Judging by this do you think I have a knackered motor or does motor sound ok??

Thanks, Dan

Hi, strangely enough spun mine by hand last week as it was very accessible at that moment(making its way from one bulkhead to another), and it too seemed less than free, as you describe, but worked fine. Are you sure you are applying electricity to it?

Nigel

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Are you sure you are applying electricity to it?

Nigel

Thanks Nige.

My electrical skills are non existent. I have checked the fuse in the fusebox below dash. Fuse in there was 20AMP (Im sure the diagram says it should be 10AMP). Anyway, it had blown so I replaced with 15AMP (all I had to hand at that moment) and blower still didnt work (although fuse didnt blow). I will get an appropriate 10AMP to replace permanently but I fear this is not the source of problem.

Where next on the electrical hunt? I feel the purchase of a multimeter coming on.

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Hi, My blower motor has stopped working (even on high speed without using resistor). Having read all the past posts on this I have checked:

duct and drain hole in woing - was full of 1" of muck and as hard as concrete but now all cleared

electrical connections - seem fine, have cleaned and WD40'd

mechanical levers - both seem to be operating the levers on the heater box absolutely fine

I have checked whether I can spin the fan using my hand in the wing. I can but I certainly wouldnt call it "free" (eg: its not like spinning a bicycle wheel upside down) however I wouldnt call it "stiff" either, could move fairly easily with a couple of fingers.

Judging by this do you think I have a knackered motor or does motor sound ok??

Thanks, Dan

You may have muck in it, or the person who put a 20A fuse in it did so cos "it kept blowing 10A ones" :ph34r: and the motor has now burnt out :angry: . Whip the electical connector (3-way) off and measure the resistance of each of the other pins to the purple / green wire with a multimeter. My guess is you'll get open circuit / very high resistance - in which case the motor is gone :(

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Thanks Errol.

Have ordered a multimeter so when that arrives may be back for some more guidance (I did say my electrical skills non existent!)

I know which 3 way connector you're referring to as I've cleaned that up/checked connection etc. BUT, for the benefit of someone who has never used a multimeter(!) exactly which leads should I be connecting where to do what you have described below?

Sorry... complete ametuer here :unsure:

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Thanks Errol.

Have ordered a multimeter so when that arrives may be back for some more guidance (I did say my electrical skills non existent!)

I know which 3 way connector you're referring to as I've cleaned that up/checked connection etc. BUT, for the benefit of someone who has never used a multimeter(!) exactly which leads should I be connecting where to do what you have described below?

Sorry... complete ametuer here :unsure:

Okay, having seperated the plug and er ... plug, you don't need the half that is connected to the bulkhead, just the heater half.

Follow the manufacturer's instructions to plug the leads into the meter. Select a low resistance range ("1k ohms" or lower) and place the meter in a secure but visible location. Apply the red lead of the meter to the purple / green wire (which would be the supply from the fusebox if it were connected) and the black lead to one of the other pins /sockets on the connector. Note the reading. If it is very high, try a higher range. Remember the value (if it comes up with a display meaning infinite resistance, try all the other resistance ranges before giving up). Move the black meter lead to the other pin / hole. You should get a different but finite value, which might be very close to the other.

If you get two values, both of which are inifnite, the motor has failed as there is no circuit.

If you get a value on one and no reading on the other, the fan should still work on high, but the wire wound resistor inside the blower casing (visible as a little panel rivetted onto the top between the fan and heater box) has burnt out.

If you get two values, a few fractions of an ohm different, then all is well in blower motor land and your fault lies elsewhere.

Make sure the ignition is off for the moment. Turn the heater fan control to full on and the meter to its lowest resistance (ohms) setting again. Approach the car half of the connector. Connect the red meter lead to either of the not purple / green wires, and the black meter lead to any handy large metal object in the engine compartment (I'll leave that one up to the reader :D ). See if you get a zero reading or not, and repeat for the other not purple / green wire. Reset the heater fan control to half on and repeat the resistance tests.

If you get a reading on one wire with it on full and the other when it is on half, this is good. No reading in either position means you have a bad earth behind the dashboard, and a reading on both wires in one position or the other means something is very wrong.

Lastly, remove the meter, turn the meter to 20VDC (or nearest value above 15VDC), refit the heater fuse, turn the ignition on and see if you get about 12V (up to 14V but unlikely) between the purple / green wire on the car half and your metal object. If so, then you are getting a live feed.

Let us know what readings you get where and we'll do some more diagnosin'

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Multimeter arrived this morning so have performed the tests as suggested with following results:

TEST 1 (on heater side 3way connection)

RED to purple/green wire and BLACK to green/yellow - 4.3 reading when set at 200ohms

RED to purple/green wire and BLACK to green/white - 2.0 reading when set at 200ohms

I assume this is telling me the heater blower motor is ok?

TEST 2a (on bulkhead side 3way connection with blower on FULL)

RED to green/yellow BLACK to engine - no reading

RED to green/white BLACK to engine - 3.3 reading when set at 200ohms

TEST 2b (on bulkhead side 3way connection with blower on LOW)

RED to green/yellow BLACK to engine - no reading

RED to green/white BLACK to engine - no reading

I assume this is telling me the dash earth is ok but my resistor is shot - dont mind about that for time being would be happy to just use the blower on FULL!

TEST 3 (testing live feed)

RED to green/purple BLACK to engine - 0.03 when set at 20VDC

Assume this is indicating a problem here somewhere??

Could anyone please tell me where I go next with this? :unsure:

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Could someone point me towards a thread which talks about removing the dash heater blower switch please?

Imagine its easy and Im being stupid :ph34r:

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Could someone point me towards a thread which talks about removing the dash heater blower switch please?

Imagine its easy and Im being stupid :ph34r:

fairly easy.

move the instrument pack towards the steering wheel

on the front facing you undo 2 screws & the small screw securing the hand grip on.

then ease the left hand slider switch out of the dash, unplug the 3 wires & make a note of which wire fits where.

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Multimeter arrived this morning so have performed the tests as suggested with following results:

TEST 1 (on heater side 3way connection)

RED to purple/green wire and BLACK to green/yellow - 4.3 reading when set at 200ohms

RED to purple/green wire and BLACK to green/white - 2.0 reading when set at 200ohms

I assume this is telling me the heater blower motor is ok?

Yes, and that the resistor for the low speed is fine (hence the 2.3 Ohm difference)

TEST 2a (on bulkhead side 3way connection with blower on FULL)

RED to green/yellow BLACK to engine - no reading

RED to green/white BLACK to engine - 3.3 reading when set at 200ohms

TEST 2b (on bulkhead side 3way connection with blower on LOW)

RED to green/yellow BLACK to engine - no reading

RED to green/white BLACK to engine - no reading

I assume this is telling me the dash earth is ok but my resistor is shot - dont mind about that for time being would be happy to just use the blower on FULL!

This tells us that the LOW fan contact (or the wire to it) is broken, the earth isn't good and or the HIGH contact is dirty.

TEST 3 (testing live feed)

RED to green/purple BLACK to engine - 0.03 when set at 20VDC

Assume this is indicating a problem here somewhere??

Could anyone please tell me where I go next with this? :unsure:

No power to the fan circuit! check the fuse, and the state of the wiring in and around the bulkhead.

Good first step already spotted, let us know what you find behind the dash! :ph34r:

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Ok, after some fiddling with fusebox and wires I now have 12.5V on the green/purple wire that goes through bulkhead to blower motor :)

....However - blower still not working :angry2:

Have taken switch out of dash and examined the 3 wires which look ok. I heard a suggestion of connecting the black wire with one of the others via a split pin which should then make the circuit and power the blower. Tried this on both non-black wires and no success on either :(

Wherever next??

Relay?

Are there some tests I can do with the multimeter on the dash or fuseboard wiring?

Do I run a cable from battery live to motor (+ an earth) and see if it does actually blow?

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there's no relay, wiring goes from switch out into engine bay across bulkhead to heater motor/resistor, if it's not running with 12v applied sounds like the motor is burnt out.

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You could check it by putting a 12v supply directly to the motor for a few seconds (hotwire if you like), this would rule out the motor.

Jason.

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Hi, I know this is an old post, but its very relevant to my problem. I have done all the checks above, and have confirmed my motor is working okay with the hotwire test.

I have 12.6V on the live wire in the 3 way connector, and continuity on the other two back to the two positions on the control lever in the cab.

I also have continuity from the wire that connects to the cab control lever, to the wires connecting to positions 1 and 2 when lever in relevant position.

Still no blower! Any ideas what else I can check?

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