bench teting a wiper motor

[ChrisC]

Seems like I am plagued by electrical gremlins in parts that i have had in storage for years...

My series 1 wiper motor does not appear to work anymore but it might be a simple case of dodgy wiring internally. Does anyone know how to bench test the wiper motor? I cant work out what the 5 wires do...

[Heuer]

The wiper motor wiring is counter intuitive but as far as I can recall the two speeds operate by switching in or out the two coils in series. This may help: http://www.mgb-stuff.org.uk/wiper4.htm

[christopher storey]

Chris : the first thing you need to do is to identify each wire . If the colours have faded you will have to do this by taking the end cap off the motor body ( don't lose the insulating sleeves off the long screws) and tracing the function of each wire. Assuming that this is a DL 3 motor the wires are as follows

Yellow : to rear terminal on coil windings ( you can't see this without dismantling the whole shebang, but if the wire disappears down towards the bottom of the casing , it is likely to be this one)

Green : to the upper contact on the motor casing ( this is the thermal cutout)

Red : to the RH brush terminal

Blue : to LH brush terminal, to which is also attached an internal wire from the cutout arrangement

White : to RH front winding terminal

Brown : to LH front winding terminal


To check the motor on the the bench , connect the blue and white wires together , connect live to green and earth to

1. both yellow and red to check the fast speed ( about 65 cycles per minute)

or 2. both brown and red to check slow speed ( about 45 cycles/min)

[ChrisC]

nice thanks gents...

i'll take a look inside the motor as yes the wiring is pretty discoloured - I thought they were 5 black wires until i scraped the dirt off and saw there was a hint of colour under the grime

[1954Etype]

nice thanks gents...

i'll take a look inside the motor as yes the wiring is pretty discoloured - I thought they were 5 black wires until i scraped the dirt off and saw there was a hint of colour under the grime

Chris,

note of caution. Make sure you connect to the correct colour. You might find the original colours under the plate that they go into. Failing that, I think Ihave a wiring diagram somewhere so you can work out what the colours are from that.

If you get the wiring wrong, you will burn the motor out and they are expensive to get fixed.

[christopher storey]

Angus : Unfortunately , the wiring diagram is of no use if the wires in the motor are discoloured, and even more so if in addition the motor has been disconnected from the loom which I believe is the case here. . I have given specific guidance on the functions of the wires, which in this situation is the only realistic means of identifying them . AFAIK It is not information which is published anywhere and is based on my experience of rebuilding a number of these motors . As far as loom connections are concerned, Yellow on the motor goes to yellow/light green on the loom . Green goes to green on the loom . Red goes to red/green on the loom . Blue to blue/green on the loom . White to white /green on the loom , and Brown to brown/green on the loom. All these for 4.2 . The 3.8 may be different but I have not looked at the diagram for the 3.8

[1954Etype]

I think I made a drawing of what went where inside the motor as I needed to desire when converting to rhd (2 wires need to be resoldered)