Heater motor

[BobE]

One for the electrickery experts

When I switch on the heater motor it will run for up to 2 minutes then stop, if I then push the switch back in and leave off for a while then switch back on it will again run for a short time then switch off again. Any ideas as to why it keeps cutting out and possible remedies would be welcome.

 

Cheers

 

Bob

[Mike Collins]

Bob,

 

Does it make any unusual noise when it stops? could be motor bearing. Are you running at high speed or low? If low it could be the series resistor. Does anything else stop working, brake lights, temp and fuel gauge? Check top fuse and contacts.

 

To prove the motor, pull the green/brown and green/yellow wires off the switch and connect each in turn, through a fuse to +12. One will be high, the other low speed. If it still fails you have either a bad ground connection or you'll have to remove the heater unit and investigate the motor.

 

Good luck.

 

Mike

[TRTerry]

I had an intermittent electrical fault where the fuse-wire had fractured under a end cap of the fuse where it is normally soldered/welded in place. When things got warm or on a particular vibration/jolt the fracture opened and my instrumentation (in this case) died. Once cool etc the fracture closed up and power was restored. Cursory inspection would not reveal the problem as the fracture was hidden by the end cap, and the fuse tested OK for continuity. I cannot recall exactly how I discovered this, other than probably found the end cap was a bit loose and the fuse-wire did not follow it when the end cap was turned slightly.

[BobE]

Bob,

 

Does it make any unusual noise when it stops? could be motor bearing. Are you running at high speed or low? If low it could be the series resistor. Does anything else stop working, brake lights, temp and fuel gauge? Check top fuse and contacts.

 

To prove the motor, pull the green/brown and green/yellow wires off the switch and connect each in turn, through a fuse to +12. One will be high, the other low speed. If it still fails you have either a bad ground connection or you'll have to remove the heater unit and investigate the motor.

 

Good luck.

 

Mike

 

 

 

Hi Mike

 

Thanks for the reply. To answer you questions 1) no noise just stops, 2) in both fast and low speeds, 3) every thing else works. I will try out the switch wireing

 

Cheers

Bob

[BobE]

I had an intermittent electrical fault where the fuse-wire had fractured under a end cap of the fuse where it is normally soldered/welded in place. When things got warm or on a particular vibration/jolt the fracture opened and my instrumentation (in this case) died. Once cool etc the fracture closed up and power was restored. Cursory inspection would not reveal the problem as the fracture was hidden by the end cap, and the fuse tested OK for continuity. I cannot recall exactly how I discovered this, other than probably found the end cap was a bit loose and the fuse-wire did not follow it when the end cap was turned slightly.

 

 

Hi Terry

 

Thanks for your reply although the fault is not intermittent I will check out the fuse and connections.

 

Cheers

Bob

[Alec Pringle]

Hi Bob,

 

motor bearings might well be the cause - lack of lubrication, friction, the motor will run until it gets hot enough to jam . . . . turn it off, cools down, then will restart for a short time until it jams again. Some heater motors have thermal cut-outs too, to guard against cooking themselves, but I don't think a standard TR6 motor has such a luxury. Mind you, AN Other motor with cut-out may have been substituted at some point in the car's past life ?

 

Cheers,

 

Alec

[BobE]

Hi Bob,

 

motor bearings might well be the cause - lack of lubrication, friction, the motor will run until it gets hot enough to jam . . . . turn it off, cools down, then will restart for a short time until it jams again. Some heater motors have thermal cut-outs too, to guard against cooking themselves, but I don't think a standard TR6 motor has such a luxury. Mind you, AN Other motor with cut-out may have been substituted at some point in the car's past life ?

 

Cheers,

 

Alec

 

Hi Alec

 

Thanks for the info you may be correct as the car is a 1970 which had only done 22,000 miles when I got it 3 years ago (now done 40,000)so it may mean the motor out Then again its not that often that I try the heater, mostly run with top down

 

Cheers

 

Bob

[Peter Cobbold]

Getting at the heater motor is a pain, the top bolt defeated me years ago,... and now the motor has siezed. I think I saw somewhere in-line motors that fit in the outlet hoses from the matrix to the cockpit. Anyone seen them?

[88V8]

Getting at the heater motor is a pain, the top bolt defeated me years ago..... I think I saw somewhere in-line motors that fit in the outlet hoses from the matrix to the cockpit. Anyone seen them?

 

Yes it's hard to get at. I managed to get the heater out without removing the speedo & rev counter, and working only from the passenger side as the car was in the garage where I can't open both doors at the same time. It is easier with the speedo/rev out. Otherwise the top bolts need a good tool-kit and long fingers.

 

Btw there are two different designs of TR6 heater motor/casing. They can be interchanged with a bit of tinsnippery.

 

The inline fans you want are on P169 of the Car Builder cat which you download as a PDF.

http://www.nfauto.co.uk/index.html

They fit 2.5" ducting so you'd have to make adaptors.

Oh, and they're £108 each.

 

Edit - also here but 3"

http://www.demon-tweeks.co.uk/Motorsport/Driver_Health_&_Hydration/Driver_Cooling/Demon_Tweeks_In_Line_Blower_Fans/1895/5427

on the other hand only £20 or so.

 

Ivor

Edited November 30, 2010 by 88V8

[jean]

Revington is making heater sets with drum fans, these will solve most problems.I have removed the Y tube and cold air ducts to the feet area, who wants cold air on the feet, they are of no use at all

A good way to clean up the area under the dash

[Gordon Bayley]

Hi Bob

Before you take things apart, try to break down the problem

Always start with the simple and easy things first

1.by bypassing the switch,

2.taking a feed from a different fuse, but still keep a fuse in the circuit

3. make sure you have a good earth direct to the battery for the test

4. if the fan fails on fast and slow it is probably not the motor

5. you could also put a test bulb in the circuit to help diagnose the problem

 

Other than that it probably could be the motor or the fan blades are sticking

I have a spare fan if you need to try it

 

I suppose your winter wish list will be a red rose bobble hat to keep you warm!

 

Good Luck Bob

Cheers Gordon

Edited December 3, 2010 by Gordon Bayley

[Denis]

I've never used my heater! I'm hard, I've never put the top up !