Internal Blower Motor not running and 40 amp fuse keeps blowing.

[John MH]

Following a reverse polarity of the Battery during a ***** up jump starting a 1.33l automatic 2012 iQ the car now runs, the engine ECU is fine but the internal fans will not run and when selected on a 40A fuse blows. Garage says it could be the Blower Motor or AC Amp could be the problem but want approx £800 to remove the dashboard and centre console to do more diagnostics and thats before the cost of any parts. Currently the car is valued at approx £3000 for part exchange, the bill is already £400 for the repairs so far so what are the options to get it fixed as economically as possible?

[Mooly]

Sorry to hear of the mishap...

I would try disconnecting the motor and then see if the fuse still blows or not when you select the fan to run. I don't know if the motor has any onboard electronics or whether all that is on the control unit but at least you split the problem in half doing this.

Polarity reversal on electronic circuitry is bad news I'm afraid but you may get lucky and find it is something relatively simple such as a suppression diode across the motor that has failed short circuit... but that is getting into the realms of electronic fault diagnosis rather than automotive electronic work.

 Whatever is taking a 40 amp fuse out is more than likely something 'hefty' rather than low powered electronics where you would actually 'blow the fault up' rather than the fault itself passing enough current to zap the fuse.

 

 

 

[flash22]

£800 for what ? seems like they are just throwing parts at it

No need to remove the dash, disconnect the fan and see if it still blows the fuse, AC or climate ?

Another thought is it could be the blower resistor, it may be a dead short

 

Thinking a bit more if its got climate the resistor pack is transistor based reverse voltage will blow it

[John MH]

19 minutes ago, flash22 said:

£800 for what ? seems like they are just throwing parts at it

No need to remove the dash, disconnect the fan and see if it still blows the fuse, AC or climate ?

Another thought is it could be the blower resistor, it may be a dead short

 

Thinking a bit more if its got climate the resistor pack is transistor based reverse voltage will blow it

Would that be the AIr Con Amp?

[John MH]

23 minutes ago, Mooly said:

Sorry to hear of the mishap...

I would try disconnecting the motor and then see if the fuse still blows or not when you select the fan to run. I don't know if the motor has any onboard electronics or whether all that is on the control unit but at least you split the problem in half doing this.

Polarity reversal on electronic circuitry is bad news I'm afraid but you may get lucky and find it is something relatively simple such as a suppression diode across the motor that has failed short circuit... but that is getting into the realms of electronic fault diagnosis rather than automotive electronic work.

 Whatever is taking a 40 amp fuse out is more than likely something 'hefty' rather than low powered electronics where you would actually 'blow the fault up' rather than the fault itself passing enough current to zap the fuse.

 

 

 

Thanks, hopefully it’s the Blower Motor as they are not to expensive. The garage estimated 7 hours work to remove and replace the dashboard and centre console hence the £800 for labour, that sounds excessive to me but it’s what they quoted.

[flash22]

Is it AC or climate ?

is it a main stealer ?

The blower motor is behind the glove box 10 min job to get to it

 

AC amp if climate is accessed by removing the centre console (climate has 1 knob and a display below the vents)

[flash22]

Just pulled up the wiring diagram the 40a fuse feeds the fan directly the Ac amp sends a signal to the fan for the speed (duty control) - That means the blower motor has an onboard controller/regulator (3 pin connector) - test and replace the blower motor

[flash22]

87103-74021 £144

not sure if it is the right one but its 3 pin from a 2011

https://www.ebay.co.uk/itm/274431075073

[John MH]

Flash22

Thank you very much for your help. Just back from Toyota Garage, latest update is that 40A fuse is not blowing and everything works apart from Fan, they still want £800 to strip out the dash and centre console to investigate further. I'll have the car home tomorrow and will check all fuses myself (I expect the garage has already done that) and look to change the blower motor to start with. I would expect that they did some computer diagnostic checks on the Air Conditioning system and that would have highlighted if the Air Con amp was defective, the manual identifies the Ac as 'Automatic air conditioning system' no mention of 'Climate' control.

 

car model is IQ3 VVT-I CVT

 

3 hours ago, flash22 said:

Is it AC or climate ?

is it a main stealer ?

The blower motor is behind the glove box 10 min job to get to it

 

AC amp if climate is accessed by removing the centre console (climate has 1 knob and a display below the vents)

What is 'main stealer'?

[Mooly]

So not blowing 40A fuse... 

Yes, you still need to check ALL fuses to be certain yourself that all are OK. If no fuses are blowing then it is looking like it could be the main control unit. This shows a typical kind of arrangement (its just a generic circuit) where the motor is supplied with +12 volts (so you need to check that). The speed of the motor is determined by how that device marked 'Q1' in the box is turned on.

Think of it as a switch. 

When the fan control signal is 'high' (12 volts) the motor runs at full speed and Q1 is like a closed switch.

When the control signal is zero the switch is open and no motor current flows.

The ratio of on to off time determines the average voltage the motor sees. For example if it is on for 100 milliseconds and then off for 100 milliseconds we could say the motor sees an average of 6 volts and so runs more slowly.

[flash22]

Main stealer - Main dealers typical overcharge for small jobs or pad simple jobs out, If you have a muiltmeter I can give you the information required

@Mooly same sort of setup but its integrated into the motor and it uses a duty cycle (in essence it uses a PWM) if you put the power the wrong way through a control board it will kill it

[John MH]

36 minutes ago, flash22 said:

Main stealer - Main dealers typical overcharge for small jobs or pad simple jobs out, If you have a muiltmeter I can give you the information required

@Mooly same sort of setup but its integrated into the motor and it uses a duty cycle (in essence it uses a PWM) if you put the power the wrong way through a control board it will kill it

I'm no electrician but I do have a multimeter, I'm thinking the Air Con Amp has probably blown on reverse power the only part number I can find is 88650 from a Yaris, any idea if this is the same or would work? Does it need programming?

Thanks again for your time.

[Devon Aygo]

1 hour ago, John MH said:

I'm no electrician but I do have a multimeter, I'm thinking the Air Con Amp has probably blown on reverse power the only part number I can find is 88650 from a Yaris, any idea if this is the same or would work? Does it need programming?

Thanks again for your time.

Toyota part number consist of 10-12 digits the first 5 are what Toyota call a PNC "part name code" and in this example all AC amplifiers start 88650 the next 5 digits narrow the part down to specific application and the last two digits if present denote a colour variation or exchange/refurb part.

For the EU market there are 21 variations of AC amplifier depending on Engine, auto/manual AC, build date and destination climate and all of them are unique to the IQ

If you PM your chassis # number I can get an exact part number for you should you need to locate one 

[Mooly]

8 hours ago, John MH said:

I'm no electrician but I do have a multimeter, I'm thinking the Air Con Amp has probably blown on reverse power the only part number I can find is 88650 from a Yaris, any idea if this is the same or would work? Does it need programming?

Thanks again for your time.

As Devon Aygo suggests, it is going to have to be the correct version for your car. My advice would be to not get to deep into this without first checking basics. If I was faced with this I would begin by confirming the motor has its 12 volt supply present, same again for the control module.    

[flash22]

Test, test and test again before throwing any parts at it

unplug the fan cable check the power and grounds (from the cable side) - then check the control and ground with the meter, turning the fan on as you check it

 

[John MH]

Found the offending item, this is the circuit inside the blower motor. I'm guessing a new (probably s/h) blower with sort the problem out.

[Gerg]

Looks like the culprit!  Well spotted!

I think that Zener diode is there to squash any back-EMF from the motor, if I remember my physics lessons correctly.

It doesn't look very well.

[John MH]

Took a while to get too, had to remove the centre column and lots of trim around the dashboard to get into it, was flying a bit blind so probably removed more than I needed to.

 

[flash22]

That will be the issue then time for a new one

the one i linked above is still for sale

https://www.ebay.co.uk/itm/274431075073?utm_source=ToyotaOwnersClub&utm_medium=ForumLinks

make an offer you might get it a tad cheaper

 

[John MH]

Ordered one from a dismantler for £30.00 hopefully it should work. if it does I'd have saved myself at least £1100 that the 'main stealer' wanted.

[flash22]

Well its all good practice, you only needed to take the glove box and surround off, drop me a pm if you want the service manual

 

Hope you purchased the 3 pin model

[Mooly]

Well done 🙂 As Gerg suggests it could well be a suppression device and I suspect it will be what is variously called a 'Transorb' which is very much like a Zener but designed to handle very high peak energy transients. Very interesting... and fingers crossed the replacement blower is an instant fix.

 

 

 

[John MH]

6 minutes ago, flash22 said:

Well its all good practice, you only needed to take the glove box and surround off, drop me a pm if you want the service manual

 

Hope you purchased the 3 pin model

Thanks. There is no glove box and it was not clear from the info I could fine which side the blower was accessed from. Its accessed from the RHS under the steering wheel and I was not sure which bits of trim had to come off as they apper to be all interlocked. I did use an online manual buts it not very clear. I'll PM for a manual if you have one, thanks. 

[flash22]

A lot of the online resources are lhd, when i meant glovebox i was referring to the kangaroo pouch option

rule of thumb is the blower is the other side of the car from the driver

[John MH]

Well the good news is I've manager to RxR the Blower with a recycled unit and now that seems to work ok. The help on here has been fantastic so thank you all very much.

I do have a couple of new problems since putting everything back, the brake system warning light is on (usually this is because the handbrake is on but it stays on after the break is released), the ABS light is on and the Slip indicator and VSC Lights are on and the Malfunction indicator lamp is on).

I hope its something I've disturbed thats causing the trouble but I'm sure all plugs were re-attached on the console rebuild and I've checked all the fuses and they appear to be good.