Blower resistor on mk1 Yaris

[furtula]

The season barely started, and  the resistor dies on me again.

The part itself is ok, it's the heat fuse that went out. I checked it out, and it should be 150-170c fuse. I was thinking of ordering another fuse and crimping it on, like it was.

Does anyone know the actual fuse part number, or the resistance in Celsius? I could not find anything when i checked the numbers from the fuse itsels.

I have the green one from the picture below, which should be for EU built Yaris. I did also have in my hand the one for Japanese built, which is just flat, and i remember checking it, and it had no thermal fuse, and was also for MK1 Yaris.

Is thermal fuse necessary, are there any DIY fixes with putting a wire of certain gauge as a permanent fix, or getting a fuse with higher temperature resistance?

I kinda get the feeling that when i fix mine with a new fuse, it won't last that long. It worked fine during summer with AC on, but the warm air is  killing the fuse rather quickly, even after few seconds the resistor does get 50-70C, and considering how fat the metal on it is, i presume it's intended to be that way, as i have seen cracks on the green thing, on both of them. 

 

[Bper]

Have you checked the air filter isn't clogged this can cause this to blow.

[DerekHa]

Hi Dean,

Would agree with Bper's comment. That fuse is meant to sit in the air stream of the heater/AC ducts to keep it cooler otherwise they will fail. A choked cabin filter or the air intake being blocked with leaves are most likely.

One other possibility is that the blower motor is drawing to much current which could be down to one of it's bearings being dried out and needs some lubrication. Have had that problem on one of my vehicles in the past.

[flash22]

Check the cabin filter, drop the motor and make sure the ducts are clear, the resistor is cooled by the airflow over it, the resistor is before the heater box the fan should still work on full speed

a high resistance in the switch may be causing the issue

 

is that a busted leg on the left ?

[furtula]

The filter is new, there was some small debree on top, but far from clogged, the filter has been in there for 600-700 miles.

The blower however is not spinning freely. When i spin it with my hands, i feel some resistance, not much, but could be that the bearings need some lubrication. I presume it should spin completely free.

The blower was mostly running on lowest setting, with air being drawn from inside, so not helping much in terms of cooling it, as opposed to outside air, and also i presume should be highest resistance in order to keep the fan speed low.

Would i need to remove the whole assembly to lubricate the bearings at the bottom, if anyone knows?

Not really keen on doing so with this weather.

@flash22 pictures are from the web, both my resistors are fine, except from blown fuses.

[flash22]

The motor is starting to fail, if it's blowing the large 30-50 amp fuse, yes lowest speed = highest resistance, the more heat it produces

[Bper]

It may be easier and better in the long run to change the blower motor .

Toyota Yaris MK1 (2005) Heater Blower Motor Fan & Resistor 194000 246460-6080.

Try eBay they come complete with resistor. Hope this helps

[furtula]

It's not blowing the main fuse, but the thermal one.

Don't know about the amps, but maybe up to 10A.

Would be nice if someone could advise on the actual fuse required, i don't want to keep collecting resistors when a 1GBP fuse is all i need.

I'll try lubricating and replacing the fuse at first, can always replace the whole thing later if it fails again, but i hope by then i'll have more fuses 🙂

 

[flash22]

are you talking about the thermal cut out on the blower resistor ??, i will have a look at the diagrams#

check the resistance of the blower resistor

[furtula]

Yes, the thermal fuse, thing sticking on top of the green resistor.

I can't find the actual values of it needed.

 

 

[flash22]

the light blue band should be 84ºc, and it's a non resettable

[Gerg]

The thermal fuses come in 10A and 20A, maybe bigger?, but I've not seen bigger.  I would be surprised if yours wasn't the 20A.

The fuse size in the car fuse box will give the clue.

It's a popular fuse/resister arrangement on say, Peugeot, Citroen and Mini.

A repair kit (fuse and two small crimps) is available (eBay) for those cars, but would obviously need to be checked that it was the same temperature and current rating as your one, the values on the fuse are usually barely legible, sadly.

IIRC, on a Mini, the fuse is rated at ~ 180 degrees and 20A.  I can't see why yours would be much different.

On the Mini I looked at, after replacing the blown fuse, some months later a slight fan motor squeak became evident (not my car btw), and the fuse blew again.  Bearings!

[DerekHa]

I once managed to lubricate the lower blower motor bearing following having the thermal restistor blowing repeatedly.

It wasn't on a Toyota I'm sure, I seem to recall it was my 2006 Madza 3. Someone had done a howto which didn't involve extracting the motor from the dash assembley. It involved drilling a small hole in the outer plastic case of the blower motor and introducing some WD40 through the hole which was directly above where the lower motor bearing was located.

Had the blower motor fail on a Renault Scenic before that and to change the motor was two day job as the whole dash and steering column had to come out.

[furtula]

I guess i'll wait until i get the fuses. 

Checked out the blower, and it's only 3 screws, but ECU is right under the blower, with a couple of more screws and cables, none of them willing to budge a bit.

Pity the car could not do this a month ago, when it was 20C outside.

[furtula]

According to fuse box diagram, the fuse for blower is 7.5 amps.

Diameter of thermal fuse is 0.8mm, and it corresponds with fusing current of 7.5 amps.

But i can't find such fuses anywhere, they are all 10 amps, so i guess i will go with that.

Still not sure about the heat resistance, so i guess i'll get a couple of different values, 84c as suggested by flash22, and upwards.

 

[flash22]

Is it just blowing the 10 amp gauge fuse, or is it blowing the A/C fuse (7.5a) ? Does the car have A\C

That thermal fuse is a one shot fuse, so non-resettable

[furtula]

I think i wrote it already, but it's blowing the thermal fuse which is on top of the resistor, not the fuse in the fuse box.

Car has A/C, in summer worked fine, in winter i don't use it, only the blower with hot air.

Yes, it's a one shot fuse, but you can buy the fuses as parts, and replace them.

 

[flash22]

ok, but what is causing it to blow, is it heat or current ? I would suspect the fan switch or poor air flow across the resistor

 

[furtula]

Wife was driving it when it died, so i don't know at which setting the fan was. 

But i'm guessing the fault is in the blower as it feels like it's sticking a bit. 

Don't have another blower at hand, but i presume it should spin freely, mine does not, causing it to draw more power than designed, especially at low speeds, leading to overheating, and fuse going out. Atleast my guess.

[Mooly]

19 hours ago, furtula said:

But i can't find such fuses anywhere, they are all 10 amps, so i guess i will go with that.

I'm afraid I can't add much to what has been said but it is important to be aware that such a fuse is an integral safety feature of the circuit and if there is doubt should be replaced by the correct type.

'10A types' as a generic term may well apply to operation at 230 volts AC and into a resistive load and if used to interrupt (to break) a high current overload in a DC circuit (12 volts DC) and where the load (the motor) is very inductive (which causes a large arc when the current is interrupted by a mechanical contact) then the 'break' current rating may need to be de-rated by perhaps 50% or more. 

 

[furtula]

According to documentation i found for mk2 Yaris, but blower looks exactly the same to me, the blower should consume from 1 to 3A of power.

So i'll go with that. The fuses are cheap so i can try a few.

Video is interesting, but the car is 12V dc, not 220 dc. The fuse is 0.8mm thick, so even if it tried carrying a higher load than car normal fuse, it will quickly overheat and stop working. 

When searching for similar things, i noticed a lot of kits with replacement fuses, most of them were 216C, 10A, 250V, but would not dare to put 216C one, i fear the blower would burst into flames before that fuse goes out.

 

Still find it weird that Japanese built Yaris has different resistor, without a fuse, but just a big piece of flat copper for one.

[Mooly]

6 minutes ago, furtula said:

Video is interesting, but the car is 12V dc, not 220 dc.

Yes, but the principle is the same. Interrupting DC current draws an arc and that is much much worse for an inductive load (like a motor). It is something to be very aware of with relays, switches and so on.

Found this from of the electronic component suppliers. It explains how these thermal fuses operate (something I didn't know... never thought about really)

  2007TOD-78 guts.pdf (farnell.com)

If you search for 'Thermal Fuses' you will bring lots up.

 

[DerekHa]

If you don't address the fact that the blower motor is stiff to turn, I presume you've had it out of the car to know that much, then it will continue blowing the correct rated fuse if you can source one. A wrongly rated fuse could cause the blower motor itself to overheat, run the risk of it melting or worse.

There's a youtube video of the fan being removed very easily.

 

Looking at the under side of the blower where the black housing holds the bottom of the fan you can see a slight circular protrusion which is directly under the motor shaft and bearing. With the motor out and disconnected drill a small hole in that area as that is where the bearing will be. Then introduce some WD40 through the hole into the bearing, don't flood it, while working the fan and you should find (hopefully) the fan will free up.  Afterwards turn the blower assembley right way up and let any excess WD40 drain out for 5 mins or so, WD40 evaporates quite quickly with little residue. Once done add a tiny amount of 3in1 oil or similar to ensure the bearing and motor shaft stays lubricated. Clean the black plastic off with something like white spirit so it's none greasy/oily and carefully apply some silcone or other sealer over the tiny hole to keep the oil inside the housing. Cheek the blower is working before refitting by reconnecting.

 

 

[furtula]

Mine is LHD model and the blower is hidden behind the glovebox. Luckily it's not so hard to remove as i thought.

-Remove the glovebox

- You will see 2 screws  holding the ECU, take them out, there's a small hook holding the ECU up, push it a bit, and free it up. On the back of the ECU there's a small holder that just pushes into place. Pull the ECU a bit towards you and it should drop down.

- Remove the blower by unscrewing the bottom 3 screws.

 

Blower 2 bearings, one at the bottom, hidden by black plastic, and not acessible. One at the top, which is acessible after removing the white blower fan.

Both need lubricating, both have some felt like material on top/bottom sides of the baring, to prevent fine dust from wearing out brushes, finding it's way inside.

I lubricated both of them, and while spinning a bit to free them up more, a bit of corrosion came out, so they were dry, the top one more so than the bottom one.

Felt like material is great for holding the oil btw,  i have them lubricated now, and sitting on a bench to soak a bit more.

I managed to identify the fuse as 172C 10a amp fuse using some russian website, which coresponds with the markings somewhat (172kr1) and the gauge of the wire.

The color code of the new fuse i found there is same as on mine.

I have ordered the new fuse locally, and hopefully tomorrow will be able to test fit it all back.

 

The part itself looks roubust and well built, but for example, brushes are not possible to change without some hammering, and the plastic is hard, but brittle, so brute force or hammer can cause to cracks.

It would be better to replace the part, but i like to try fixing it first. I'm not UK based, and there are plenty of parts here, but that involves bunch of calls, so figured to try the DIY route first.

 

[flash22]

The motor isn't the issue as it not blowing the fuse, it's not blowing the control side fuse either it's blowing the thermal fuse

either the lower speed resistor has gone high resistance, there is no air flow across it - the only other factor is the switch has gone high resistance as it is on the tap points for each resistor

A simplified generic blower motor diagram