Heater blower

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styleruk

styleruk

Active Member
Posts
128
One of the jobs I want to quickly do on my recently bought 85' 90 is get the heater blower working.
Checked the fuse today, it's blow, fitted a new one, it blew.
Checked the wiring going to the heater box in the corner on top of the bulkhead, all the wiring looks good and it does not blow when unplugged, so I'm assuming the motor is screwed.
Resistance between live and earth from the motor is non existant, so I don't think it's damp causing the blow, but may be wrong.
The heater box is pot riveted up, is it a case of drilling out those to get to the fan...the wires drop down a circular hole into a part of the box sticking out, I assume the fan is in there? Or, do I (god forbid), have to take the entire matrix unit out and do it on the bench...if so, it's gonna be next weekend!
 
Taking the matrix out completely does make life a lot easier as (yes) the box is riveted together and need drilling out to dismantle.
Here's a picture of mine out the car.
You can see the wire going ito the plate on the top, thjat has the resistor underneath which controls the speed. The green and black wires that go into the round motor should be accessible.
What I suggest you do is put 12V on those two wires (using a 10A in line fuse) and see if the motor runs.
If it does then reconnect it and put the 12V onto the three way connector, if you get fast and slow speeds then you have a wiring issue between the switch and the resistors.

HeaterOut.jpg
 
The bearings are oiltite ones, after a few years they lose their oil and then seize to the motor shaft, this then spins the bearing in the housing until that to seizes, which is why they blow fuses.
You can with some faffing get a spray nozzle in there and lube the bearings, though it will not last long.
In the end you will need a new fan assy.
 
miktdish said:
Taking the matrix out completely does make life a lot easier as (yes) the box is riveted together and need drilling out to dismantle.
Here's a picture of mine out the car.
You can see the wire going ito the plate on the top, thjat has the resistor underneath which controls the speed. The green and black wires that go into the round motor should be accessible.
What I suggest you do is put 12V on those two wires (using a 10A in line fuse) and see if the motor runs.
If it does then reconnect it and put the 12V onto the three way connector, if you get fast and slow speeds then you have a wiring issue between the switch and the resistors.

View attachment 304618
Click to expand...
That small plate riveted down, what's under that. Is there something I can check there before taking out the whole thing? It might be something simple like a shorted wire.
 
miktdish said:
You can see the wire going into the plate on the top, that has the resistor underneath which controls the speed.

Click to expand...
OK, might be worth checking that out first, I can get to that without removing the whole thing, but of course, if I don't see anything it all has to come out. I'm guessing it's a jammed motor but could be the reisister.
when I checked it did nothing on level 1 speed, that means the resister could be taking all the load and the motor jammed and not enough to blow a 10a fuse. Setting 2 lights the fuse up and blows it, I'm kinda thinking a jammed motor that has not been used much, might be able to spin it by hand if possible to get it going, otherwise.....take it all out.
If the resister is under that plate, it'll be easy to check.
 
styleruk said:
OK, might be worth checking that out first, I can get to that without removing the whole thing, but of course, if I don't see anything it all has to come out. I'm guessing it's a jammed motor but could be the reisister.
when I checked it did nothing on level 1 speed, that means the resister could be taking all the load and the motor jammed and not enough to blow a 10a fuse. Setting 2 lights the fuse up and blows it, I'm kinda thinking a jammed motor that has not been used much, might be able to spin it by hand if possible to get it going, otherwise.....take it all out.
If the resister is under that plate, it'll be easy to check.
Click to expand...

I guess you are struggling or i'm not explaining myself correctly.

Under the rivet lid is the resistor.
it's a 4 Ohm wire wound resistor, probably 50W, here's a pic ...

res.jpg


Pushing the speed controller all the way down feeds 12V directlt to the fan, via one end of the resistor (light green wires) to the the 2 way connector.
One click up and the power goes into the resistor via the blue wire, through the resistor and up the green wire to the motor.

The 2 pin connector can be unplugged and 12V fed straight into the fan motor.
This will check the motors operation.
If it spins, it not the motor, if the wires get very hot very quickly and the motor doesn't turn, you've found the problem.

You can also unplug the 3 way connector and apply 12V to the purple and light green wire, if the motor spins the fault is possibly between the binnacle/switch and the 3 pin connector, connecting to the blue and purple wires on the 3 pin tests the resistor.
The motor will spin slower if the resistor is OK (it probably is).

In their infinite wisdom LR has a small section of the wiring between the switch and the 3 pin connector that is quite thin.
It runs below the tray under the dash and is prone to melting/shorting out.
The work around is to run some new cables from the binnacle, out to the engine bay, along the bulkhead and connect them to the 3 way switch.

Here is a link to some cable.
Use the 3 core 16A

Multi core thinwall cable avaiable in 2, 3, 4 and 5 core.

Multicore Cable
www.vehiclewiringproducts.co.uk www.vehiclewiringproducts.co.uk
 
miktdish said:
I guess you are struggling or i'm not explaining myself correctly.

Under the rivet lid is the resistor.
it's a 4 Ohm wire wound resistor, probably 50W, here's a pic ...

View attachment 304800

Pushing the speed controller all the way down feeds 12V directlt to the fan, via one end of the resistor (light green wires) to the the 2 way connector.
One click up and the power goes into the resistor via the blue wire, through the resistor and up the green wire to the motor.

The 2 pin connector can be unplugged and 12V fed straight into the fan motor.
This will check the motors operation.
If it spins, it not the motor, if the wires get very hot very quickly and the motor doesn't turn, you've found the problem.

You can also unplug the 3 way connector and apply 12V to the purple and light green wire, if the motor spins the fault is possibly between the binnacle/switch and the 3 pin connector, connecting to the blue and purple wires on the 3 pin tests the resistor.
The motor will spin slower if the resistor is OK (it probably is).

In their infinite wisdom LR has a small section of the wiring between the switch and the 3 pin connector that is quite thin.
It runs below the tray under the dash and is prone to melting/shorting out.
The work around is to run some new cables from the binnacle, out to the engine bay, along the bulkhead and connect them to the 3 way switch.

Here is a link to some cable.
Use the 3 core 16A

Multi core thinwall cable avaiable in 2, 3, 4 and 5 core.

Multicore Cable
www.vehiclewiringproducts.co.uk www.vehiclewiringproducts.co.uk
Click to expand...
When I was refurbishing my heater, I priced the resistor thinking I would just renew it while I was in there……£75 😳
The old one went back in.
 
An update and closure, thanks to all who replied and explained some things. I took it out the weekend, stripped it and the motor did not turn at all.
Checked the resister, that was good.
Stripped the motor down to the core, it was a mess, cleaned it, greased it in the right places. Knocked up new brushes and re soldered the brush connectors, they looked a bit naff.
Re-sprayed everything, once I started doing that I cut out new foam seals for everywhere.

Took a few hours but I now have a working fan, works much better than my old Singer smiths fan, actually blows air at you.

Alas, on refitting, I accidently broke one of the window washer jets...FFS, that's this weekend I guess.
 
Oh bugger. I had a week of lovely heat, then this morning half way through my journey the blower was not ...well....blowing in the cab. Fan was blowing ok and blowing air through every gap in the heater box but not much through the vents in the cab....my suspicion is the new foam bit I made for the 'flap' (that directs from top to bottom), has come unstuck and blocked the hole or something.
Odd thing is, just now (in my lunch break), I tried it and it was blowing through the vents lovely. But when I warmed it up, nothing was coming out. Very odd behaviour. Sounds like I'll have to whip it out again at some point.
 
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