Heater Stopped Working

[Robsey]

See if speed 4 works, with the thermal fuse shorted and ignition is live.

If it does, then the whole resistor pack needs replacing.

If it doesn't work, then the resistor pack is not the first place we need to look.

Have you tried firing up the motor, say with jump leads from the battery to bypass the whole of the car's wiring?

Connect the jump leads to the two male spades of the motor that the resistor pack normally connects to.

If the motor spins, then it is okay.
If the motor is dead, then that will be your issue.

[blowfelt]

Does it matter which jump lead (live /earth) I connect to the spades or doesn't it matter.

[Robsey]

It shouldn't matter a huge amount,
But...

If you connect up in reverse, the fan will suck all the dust and leaf parts out of your cars trunking, and blow it out into your face in the engine compartment.

If you connect it the correct way, it may cause any loose debris to be blown into the cabin.

So either way, make sure that your face is not in the firing line of any flying particles.

[blowfelt]

I tested the fan with the leads and it works.

I shorted the thermal fuse again just to make sure I did it correctly,the fan works on all speeds.

Robsey,you state in your posts below that it was down to the thermal fuse if the heater works on all speeds when shorting the thermal fuse.

viewtopic.php?t=9602

So I need to replace the thermal fuse then.

[Robsey]

Yes indeed.

Just the thermal fuse is needed.

Although if you cannot be faffed repairing the current resistor pack, new ones are still available.

-------------------------------------------------

Strange how it didn't work when you shorted it before.

I assume you have refitted the motor in the car, connected the plug and shorted the thermal fuse for your last test.

[blowfelt]

I first shorted the thermal fuse using the two wires that come out of the fuse and the motor did not fire up. The 2nd time I shorted the thermal fuse I shorted it on the two wires coming out of the resistor and the motor fired up.

Yes, I had the power on the ignition and motor on both the times I shorted the thermal fuse. It also depends on which wires you use to short out the thermal fuse.

I cannot get the fuse (SF214E) from anywhere in the UK, I have to order one off eBay which will take 10 to 14 days due to it coming from China.

[Robsey]

If it was not the two thermal fuse mounting prongs that you shorted, then it sounds like the whole resistor pack is knacked.

[ilovedmymantas]

- if you want to confirm it's the fuse and not the resistor pack in the meantime, you can get one by the weekend here
https://www.ebay.co.uk/itm/Microtemp-Ax ... 1438.l2649

matt

[blowfelt]

I have fixed the heater blower,it was the fuse.

I was given a fuse by my local electronic store because the writing on the fuse had almost rubbed off.
I soldered the fuse onto the resistor and it worked.

Many thanks to all who helped.

[Robsey]

I wouldn't hold your breath.

Solder melts at a lower temperature than 216°C.

So chances are, the thermal fuse will get hot, and the solder may melt, resulting in the thermal fuse falling off again.

I think solder melts at about 183°C, so a 33°C margin where the solder could fail before the fuse.
Depending upon what caused the fuse to fail in the first place -
Normally excessive current draw from a motor passed it's best / running on less than optimum brushes and bearings.

As said, the only long term method is to use the brass terminal strips out of a connecting block.

[blowfelt]

Well, I will have to wait and see hopefully, it will hold out.

[tom50]

My Blower motor on my cav is squealing intermittently, I have sourced a 2nd hand motor (working) What is involved in removing and installing it, I have had a quick look under that plastic cover on the bulkhead, the motor looks to be secured by a bracket 2x self-tapping screws to the body of the car, and the motor looks like it will slide out of the plastic cowling that surrounds the fins of the fan , is this the correct way to remove it? or does the black plastic cowling need to be unbolted from the bulkhead? If it's just the 2 self-tappers then i may be able to do it without removing the wiper arms ect if the fan on the motor will slide past the thin plastic trim that covers it

[Robsey]

From memory, the motor is held down via a curved metal clamp.
As you say, two self tappers hold it down.

In the past I have unscrewed the cowling to give full access to the motor, connector and resistor pack.

Not a tricky job at all.

Whilst in the scuttle channel, I removed the big black plastic deflector, in order to check for water leaking past into the cabin.
I also re-sealed it with gasket paste before screwing it back down into place.

As for squealing intermittently - mine is doing this too, but only when it is really cold outside.
It is usually dry bearings, so often cured by dripping 3-in-1 oil onto the bearings at each end of the armature as it emerges from the motor body.
Not particularly easy at the fan blade end.

Careful how you handle the fan blade assembly.
There are very tiny, flimsy staple-like balance clips fitted to the plastic blades.
It is quite easy to dislodge these balance clips if you are not aware of their presence when handling the fan assembly.

[tom50]

Not seeing any balance clips on the fan blades ??? this motor is out of a calibra and is the same as the cav one, maybe they no longer put these clips on them? As for lubricating the bearings which look like they are sealed, My mate reckons that once they are squealing oil won't cure them because they will be damaged

[Robsey]

Hmm - I think your friend has generalised on the level of wear or damage.

The majority of motors that have been oiled, have responded well to the lubrication.

I suppose it depends on the specific drip oil used, and how "damaged" the motor bearings have been allowed to get.

I oiled my fan about five years ago, and it has been quiet and free running apart from during the recent hard frosts.
Again, now that the temperature has risen a little, my fan is quiet again.
My fan is still the original unit from 24 years ago (and 270,000 miles).

[tom50]

That has lasted well, The bearings threatening to seize up or cause the fuse to blow, on a cold /freezing day is the time you depend on the heather working that and when it's raining, I may check the scuttle for leaks as I get the condensation issue in the winter months, though it could be down to a door seal,

[ilovedmymantas]

I've been needing to change the thermal fuse for a while now.
I don't mind only having top 2 speeds (apart from the occasional screeching ) but that's all I need in the cold weather

I'll be taking the motor out to check & oil the bearings of course, It gives me a chance to examine the scuttle for leaks-bonus

Because the thermal fuse is a common failure ( I've replaced twice in four years ) I looked for another option.

The thermal fuse in my 'vacuum cleaner' resets when it's cooled enough. With that in mind I looked about.

I wonder if something like this would do the job? It's the best I've found so far.
https://www.ebay.co.uk/itm/RH-Tf-95-115 ... 2084106422


-230 degree one, the link defaults to 115

Would you wire 2 in series for the 30A fuse rating?

I thought of it as an early- warning system for the motor, with the benefit of not losing lower speeds, even if they are intermittent

[iangsi]

https://www.ebay.co.uk/itm/RH-Tf-95-115 ... 2084106422

-230 degree one, the link defaults to 115

Would you wire 2 in series for the 30A fuse rating

Eer, no is the short answer

[Robsey]

For 30 amps they would be wired in parallel.

But I am not sure how the thermal fuse would work in that configuration.

For safety reasons, I would agree with Ian and say no.
(Sod's law and all that).

[ilovedmymantas]

Ok. Thanks guys

Regular method it is then

[Robsey]

When I had an Austin Maestro in the early nineties, it was fitted with a bi-metallic thermal-trip strip to do exactly what you are describing.

It was made by Otter Controls at Otters Ole in Buxton and fitted within a Delonair loom.



I was lucky because I got a free sample from the Buxton company after enquiring about availability after mine broke in the early nineties.

Sadly that is 20-odd years ago, so I cannot see the company or part being available.

So you could look for a mid-eighties Austin / Rover / Jaguar heater panel loom (behind the dash) in the scrap yard or ebay.

I have found a thermal trip for a Sierra on ebay... but not much else.

I have looked online, and Otter Controls do still exhist, but mainly for domestic appliance safety controls.
Their site lists safety cut-offs and thermal trips etc.
If you really want to go down that route, you could ring them.

[ilovedmymantas]

Thanks for the extra info Rob, old ad's are great.
I like seeing things I've never heard of before in adverts from way back

On reflection, I've decided to just do it the proper way.
If it had been easy I thought it would be worthwhile but it's way too much hassle.

[Robsey]

I am sure that they could assist you if you change your mind.

They are also a test / research facility, so could give advice to suit the criteria for making a bi-metallic motor protector for a Cavalier.
Approx 216°C and 30 amp capacity if I remember correctly.