Dead Headlamp Motor

[Brm Brm]

Anyone got any tips on what goes wrong with Headlamp motors? L/H pod motor stopped the other day although the lights are working normally. I assume its the motor switch box or diodes - having looked in the Bible and at the Wedge Pages headlamp article. With the motor out I cant see anything wrong with it but are there any ways of checking before I give Rimmer Bros a ring? In particular, assuming the motor wiring is standard what colour wires should have power when the lights are switched on, so I can back track? Fuses and Relays are OK - any tips appreciated??

[danny hoffman]

I have a couple of spares I took of a TR7 in the breakers yard, if you get stuck.

Have you tried dismantling them and checking if the brushes are ok, and see if the windings on the commutator looked burnt.

Danny

[Excession]

Had the same problem on BOTH of mine. If anyone was at Duxford this year and saw a red 390SE with one lamp stuck up - that was mine.
It seems that the bushes get dirty in the motors, not usually a problem with the relays or anything. Mine would go down.... but not go up reliably.
Solution is to strip down the motor assembly and clean/replace the bushes. Worked a treat for me.

[Brm Brm]

Thanks guys, I've stripped it right down - brushes are good, the windings are filthy but look OK. I connected the motor constant feed and earth wires to the battery and still as dead as a door nail - surely that should have provoked it if there was any life left at all!
Will give Rimmers a bell in the morning!

[2 sheds]

There is a manual knob at the back of the motor, sometimes turning this can suddenly get it going , mind your fingers though.
Tim

[SEVANS]

Have you cleaned up the switch block on the side of the motor? I have had a few problems with water getting in and the contacts corroding.

[danny hoffman]

If the windings look filthy they are probably burnt out

Danny

[wedg1e]

Try cleaning the commutator (the area of the armature where the brushes make contact) with very fine wet & dry. You're aiming for an even bright copper finish.
Also, run a craft knife blade between each copper segment to dig out all the carbon.
If you have access to a multimeter and know how to use one, pick any pair of segments diametrically opposed to each other and measure the resistance. There should be a few ohms, and any opposed pair should measure roughly the same as any other pair. If you see lots of 0.001 ohms or similar, or everthing reads infinity, then as Danny says, der vindings ist kaput!

Ian

[dickymint]

inside the gearbox there is a copper strip that rises up and down on both sides via a cam. give each underside of the strip a clean to remove any oxidisation. but be careful not to bend it as its a bugger to reshape to get a good contact