Heater Stopped Working

[blowfelt]

Please,could someone help me solve my heater issues,it stopped working 2 days ago.It had been making a noise for ages which I thought was maybe a leaf stuck in the motor/vents.I know it could be two issues,the motor or the resistor.

I have to get it fixed asap due to the weather misting up my windows at this time of year.Any help today would be much appreciated due to it being cold today,and maybe cold for some time to come.

[Cavalier342]

Could well be the motor bearings had gone dry/dirty over time and partially seized up, causing the thermal resistor to overheat and fail effectively. The only way to tell would be to remove the blower unit and test it.

[blowfelt]

Is it possible to test the motor by shorting across the thermal fuse on the resistor.

[Cavalier342]

I think that's how people do it, the resistor is just there to control the different speeds as far as I know. Also try rotating the fan by hand, it should spin easily, if it feels a bit stiff and stops immediately, then you know the bearings are mucky/dry.

[Robsey]

Is it possible to test the motor by shorting across the thermal fuse on the resistor.

Only for carrying out a brief test.

As with any fuse, it is a safety device.
It is intended to prevent the motor from getting to hot and self igniting.

You could short the fuse wires on the resistor pack, but you are only masking the issue, with potentially unsafe consequences.

You need to free-up the motor or replace it, before shorting the thermal fuse with anything other than another correctly rated thermal fuse.

[blowfelt]

I have noticed the bottom hose coming from the header tank is leaking.This couldn't be the cause of the heater or motor packing up could it.There is still water in the tank.

[T1BBST3R]

Not sure if it helps but on mine (heater resistor was kaput but still got fan speeds 3 and 4) the actual on-off wheel went stiff on setting 3 once and as I pushed it down, (not too hard but enough to notice a bit of extra resistance from the notch) the heater completely stopped working and all I did was replace the wheel (then resistor to get speeds 1 and 2) and it worked perfectly.
Only cost 4£ for a second hand switch off fleabay. Took the broken wheel apart and it had arced through setting 3, causing the switch to break.

[blowfelt]

Are heater blower motors the same in petrol and diesel cavaliers.

I spotted a leak on the header tank bottom hose,there is a small crack on the shaft where the bottom hose connects to header tank.Can header tanks be repaired with plastic weld bc I'm having trouble finding a replacement header tank for my 1993 Cav TDi.

[blowfelt]

I have fixed the header tank leak.

I can spin the white plastic grill on the heater blower with my hand,does this mean the motor is not seized.

[Robsey]

The rubber hose is not listed as being specific to any engine type.
So in answer to your question, if you can find a hose for any Cavalier, it should be okay.

If the motor spins freely without any apparent stiffness, roughness or drag, it should be okay.

With regard to the switch... now that you mention it, I do recall stripping and cleaning one of my switches a few years ago.
I seem to remember that speeds 2 and 3 were the same.
All the copper tracks inside the switch were filthy.
A good clean of the tracks brought the switch back to fully working condition.

[blowfelt]

Robsey,it wasn't the header tank hose,it was the actual header tank itself.

There was a crack on the little pipe that comes out at the bottom of the header tank where the hose connects to the header tank.There is also a copper/brass tube that sticks out of this little pipe which I pushed further into the header tank to cover the crack.I reconnected the hose and positioned the jubilee clip to the very end of the hose and tightened it up over the crack which fixed the leak.

[blowfelt]

How do I remove the resistor from the heater motor.

[Robsey]

Cut the stiff wire with some wire cutters, to cut out the thermal fuse itself.

Using the metal inserts from an electrical connecting block, to joint in a new thermal switch.

Not pretty, but cheap and effective.

Here the Vectra-C.com how 2 instructions, but apart from location, methodology is roughly the same.

then remove the resistor pack located at the back of the fan housing on the right hand side underneath. ( it just clips out).

once removed, cut the old thermal fuse out ( i used a dremmel drill) and clean the two pillars up so they make a clean contact.

then take some terminal block and cut one off making sure you remove the plastic as the resistor pack gets pretty hot and it WILL melt.

mount the terminal block onto a screwdriver or similar and cut it in half with the dremmel to make two pieces.

then place the two cut pieces onto the ends of the resistor pillars that you cut the fuse off

then take the thermal fuse ( Maplin p/n RA23A - "240c Thermal fuse" - 82p.)
and trim it to size leaving enough on each end to be bent over ( BEING EXTRA CAREFUL AS THESE ARE VERY FRAGILE AND TEND TO SNAP) at right angles and slot them into the two trimmed terminals.

then assemble making sure you tighten then up pretty well and refit onto the fan housing.

Obviously noting that Maplin no longer exhist.

[blowfelt]

Rodsey,is it only down to the thermal fuse that packs up on the resistor or can the whole resistor be faulty.

[Robsey]

If you lose multiple or all speeds, it is the thermal fuse.

If it is just one speed that is lost, or two speeds are the same, then it is a resistor.

A failed thermal fuse can be replaced using the method above.
Costs less than £1 for a thermal fuse...
From Farnell, RS or Ebay.

A failed resistor will require the whole resistor pack being replaced.

About £20-odd last time I looked.
Plenty on ebay, but be sure you get the correct one. There are 3 different formats / shapes.

[blowfelt]

I have never had limited speeds on the heater blower it just stopped working for no apparent reason.

I have tried shorting the thermal fuse with the ignition turned on and the fan set to position one but the fan won't spin (I can spin the fan with my hand) or make any noise.

[blowfelt]

The thermal fuse on my Cavalier TD heater resistor is "SF214E" (10A...250V...216C).

[Robsey]

Okay simple check list.
1 - Fuse is okay?
2 - Relay is okay?
3 - Switch is okay?
4 - Thermal Fuse is okay?
5 - Ignition Live when not cranking feed is okay from Ignition switch (15a)?

[blowfelt]

Is the relay in the engine bay, and what colour is it.

[Robsey]

Sadly, this I cannot advise, as my laptop with TIS2000, GlobalTIS and various other programs has been dead for a few months.

I simply do not know.

[blowfelt]

Robsey, are you sure there is a relay for the cavalier TDi heater blower. I have been searching the tinternet for 2 days but I cannot find anything related to a heater blower relay for cavalier TDi .

[Robsey]

Just had a look with fresh eyes.

You are correct, there is no relay...
I looked at the wrong motor on the diagrams.

It is a super simple circuit.

Fuse F4 rated at 30 amps.
Direct to the switch.
From the switch to the motor.
And to earth.

Check the fuse socket, to see if it is dirty or melted.

[blowfelt]

Ok, will do.

I think it is the thermal fuse on the resistor now.

[Robsey]

If you have shorted the thermal fuse with a good sturdy piece of wire, then the fan should run at all speeds with the ignition on.

In an earlier post you said you had tried this but the fan still did not run.

I presume, you have checked the earth tag for the fan?

Should be a very fat (4mm csa) brown wire connected to earth somewhere in that gully. Probably bolted to the body near the wiper motor.

We are back with the main items.
Ignition live feed.
Fuse 4
Switch
Blower motor
Resistor pack
Earth return.
And all the wiring and connectors on the way.

[blowfelt]

Robsey,is it possible the whole resistor could be buggered or is it just down to the fuse that stops the resistor from working.