Help with heater motor

[Foz31]

Evening all, as usual I’d value your help and advice...
My heater’s packed up all together...I have a series of head-scratching questions

I can get a voltmeter reading across the 2 wires (yellow and black) so I’m assuming the motor is getting power.

So I removed the motor and partially dismantled. I emery-cleaned the copper pick up and the spade connectors but still no action when wired back in. Is there anything I can try with the motor before having to replace it? Any pointers on part number or likely sources of a replacement?

The wiring in is weird - the yellow wire is soldered across the plate in the photo below...does that look right?

I found a spring in the footwell after dismantling (picture below)...no idea where it sprung from Where does it go?

And where do the 2 springs in the photo below go - between the motor body and the circular cover?

As you can tell I’m out of my depth and still only ankle deep

[longlegslandyman]

Hi yes wiring is correct black is negative the two yellows are the speeds slow and fast.
The yellow that is soldered to the other on one end of resistor gives you fast speed.
The other yellow gives you slow speed as it goes through the resistor before feeding the motor.

The spring is for the side vent flaps holds the flaps in the open or shut position.
applying voltage straight across motor should make it spin at fast speed if all is well.

So on the resistor you should have voltage one end then change fan speed switch and the voltage should change to the other end of the resistor if all is well with the switch.
If you get a voltage on either end of resistor depending where you have switch , but only one speed on motor the resistor has gone

[Foz31]

Thank you! Of course - it’s the resistor...doh!

I’ll continue voltage investigations.

Where do the 2 springs go?

[AR4412]

Hi Foz,

The two coiled springs fit inside the motor over the casing clamp bolts, fitted just before the casing goes back on.

Seen here on Bob's rebuild thread. (Hiya Bob! . Thanks for the piccies.)

https://forum.militarylightweight.co.uk ... 6&start=30

Regards,

[Foz31]

Thanks Neil, as ever.

I’m getting a reading across the wires AFTER the rheostat so I’m assuming it’s OK, or at least allowing flow through it which is good enough for me. I passed 2 9v batteries in series across the motor terminals and nothing doing - it’s also really stiff to rotate the spindle. It did get a proper dunking in my last foolish off-road caper, so I think it’s goosed.

I can only admire Bob’s refurbishment with utter respect...I wouldn’t know where to start on a repair so will look to replace. Is the motor a standard 3 series heater blower motor or is it different for a Lightweight?

If I transfer over the fan blade, does it need balancing or anything tricky?

Thanks

[AR4412]

I know the part numbers are different, and I believe the overall dimensions are different in regards to motor body length, mounting flange position on the body and spindle length. Unfortunately, the only Series we have around here at present doesn't have it's heater anymore, so unfortunately I can't compare the motors. I'm not saying one couldn't be made to fit and work okay, but have never tried it out.

I wouldn't have thought the fan would need balancing.

[Foz31]

Thanks again Neil.

I called Dunsfold DLR to find Philip has retired and closed

Replacement ordered from Blanchards...a self-gift for the New Year

The radiator was caked in mud from my dunkings so better off for a clean-out.

[Foz31]

Happy New Year everyone...let’s hope it’s a big improvement on the last.

My “new” heater motor arrived...I say new...it was in the original sealed Smiths packaging dated 21st Oct 1971 It’s nearly as old as me! Given its age do I need to relubricate the spindle, and if so, what would you recommend? I have no idea if the original lube will have degraded.

The spindle was about 10mm longer than the original and fouled on the bulkhead so I cut it down.

I’ve managed to dislodge the positive yellow wire from the right hand end of the resistor and I’m struggling to resolder it back on. I just can’t get the solder to bind on the resistor plate. Any advice appreciated...thanks

[Johnsboy]

Just make sure it’s bright and clean, you might have to rub the connection tab and wire strands up with a bit of emery cloth or sand paper. If they’re dull and tarnished you’ll struggle. Add a generous dab of flux to help clean it and make the solder run. If your using flux cored solder sometimes it’s not enough, I tend to use general plumbers flux to help clean anything I solder, especially wires and terminals.

Regards
Johnny

[Foz31]

Thanks Johnny