Wiper Motor/Heater

[Sweeny]

To the wise and humble people of the MMOC,

I have come across a slight issue with my heater and wiper motor on my 1968 Traveller (just when things started to work ). My wiper motor is not showing any signs of life. My heater however (which is wired to the wiper switch in the dashboard) I know works so I ask, is there any way to test if the wiper motor is bust or if its my wiring loom thats at fault, I have checked all the earths I know of in that circuit, I've checked the fuse box and most of the other likely culprits, I fear testing the motor off the car with a battery as, it having three terminals, I don't want to cause damage to the device.

I thank you all in advance, cheers

Tom

[oliver90owner]

First, are you sure the fault is electrical and not mechanical?

Have you checked for voltage at the motor? 'Parallel up' the loom and earth wires as extra conductors?

[SteveClem]

When mine stopped working I just cleaned up the points on the motor, sprayed everything with wd40 or similar,and it's been fine ever since.

[Sweeny]

Thank you all for your prompt replies, to answer several questions, I am not sure if the problem is electrical or mechanical. I am assuming electrical due to the heater also not showing any signs of life and the heater being attached to the wiper switch, happy to be told otherwise if this effects the wipers. If it was mechanical would it be possible for a broken wiper motor to cut power to the heater? When I have a spare second (becoming rarer and rarer) I will take a picture of the wiring on the wiper switch hopefully confirming I have rewired it correctly

In the coming days I will, as its an excuse, I will clean the points and report back

How would I go about checking the motor has the correct voltage? (I'm still getting to grips with this all! )

Many thanks to everyone in advance,

Tom

[simmitc]

In the first post you say that the heater is OK, then above that it isn't working. Could you clarify? Is everything else working OK? From memory, the heater and wiper share a common earth. Also check the fuses on the bulkhead in the engine bay.

[Trickydicky]

The heater just takes it's feed from the live side of the switch according to the wiring diagram at the head of this page. You really need a multimeter to check for voltage before doing anything else.

[Sweeny]

Apologies for the confusion in this matter, and the delay in a reply, life can get busy in an instant!

Yes the heater motor I know to be functional as it was tested outside of the car separately using a battery, sorry for the confusion. From everything that is suggested I'm hedging my bets with the common earth being at fault. Does anyone know if the earth at the point after the heater is connected to the body or is it earthed later in the loom?

Cheers,

Tom

[biomed32uk]

The wiper motor works by switching the earth if that makes sense, the green wire to the motor is a permanent (ignition switched) live, the other two are earths, one is permanantly earthed for the self parking and one is the switched earth via the dash switch.

So all of the wiring at the switch is at earth potential, don't use it as live feeds for anything as it will only show a possible 12volts when the wipers are off, the 12v coming back through the wiper motor.

The heater uses the wiper switch as a ground point, the live on mine for the heater is on a bullet connector that dangles down if I remember right.

[Sweeny]

Thought I'd post a (hopefully) last update, I have narrowed down the issue to be in relation to the switch and it's earthing. Thank you all for your help, if the electrical gremlins return and it's a red herring I'll post back.

Many thanks to all

Tom