Wiper stopped functioning

[earckens]

Suddenly my wiper motor stopped working. 12V does arrive at the number 1 connector and when I short number 2 connector to ground it starts turning.

 

A red wire, coming from inside the housing to a connector at the drive gear (grounded: when I measure there, it seems connected to ground..) is open circuit measured between the drive gear and the end inside the motor housing near the brushes.

 

I believe it is a one-speed motor (only two wires plus coming in and one to ground); excuse my ignorance: we got the car just a few months ago and in Southern France it does not rain in summer

 

Included I have a electrical manual for the wiper but it is 1. in French and 2. for a 2-speed, so I do not know if part 2 makes it useless?

 

What should I be looking for first when tackling this problem?

 

Any help is much appreciated!

Erik

 

2 speeds WIPER motor.pdf

[RogerH]

Hi Erik,

the top red wire is for the 'self park' facility

 

Yes - one speed motor.

 

here is a good wiring dirgram http://www.advanceautowire.com/tr24a.pdf

 

The green wire is +12V

Black = earth

Green/Black goes to the dash switch.

 

Roger

Edited November 15, 2016 by RogerH

[earckens]

Hi Roger,

 

just one wire to the dash switch? Would you not need a second wire? One wire to bring 12V from the dash switch to the motor, a second to short both wires and allow 12V to run as long as the park switch is not active? As park switchis active, it stops the 12V which came from the park switch..?

 

Since I measure an open red wire from the park switch it would mean no return to ground from the motor, so no wiping?

 

Funny is that when I short the middle wire (noted 2 on the second picture) to ground the motor turns (when the dash button is activated and 12V is on number 1)??

 

Erik

[RogerH]

Hi Erik,

one wire (Green/Black) goes to the switch from the motor and the other side of the switch goes to ground close to the switch.

 

The motor is always powered and the earth is switched.

Roger

[earckens]

Hi Erik,

one wire (Green/Black) goes to the switch from the motor and the other side of the switch goes to ground close to the switch.

 

The motor is always powered and the earth is switched.

Roger

I have negative earth: same wiring?ED

 

EDIT: but on the second picture there are three wires connected to the motor: number 1 carries the 12V from the switch, the third connects to ground; but number 2 ???.

Edited November 15, 2016 by earckens

[RogerH]

Hi Erik,

when the TR4 changed to neg earth the wiring to the various bots did not change.

So #1 = Green = 12V+

#2 = Green/Black and goes to the switch

The thrid wire is earth to the body.

 

Although the attached wiring diagram shows it as +ve earth it makes little difference to the main wiring loom.

 

Roger

[earckens]

Ok, thks!!

 

So high probability that, since I measure open circuit on the red wire, it causes the motor not to function.

 

I will check on site, will be mid december: I keep you posted.

 

Erik

[RogerH]

Hi Erik,

the RED wire is the self park wire.

It is only connected (to earth) when the motor is turning - AND then for only 340 degrees.

It connects the motor to earth when the dashboard switch is turned off. - the red wire stays connected until the blades get tot he bottom of the screen.

 

Roger

[earckens]

Hi Roger, when measuring through the red wire I read an open circuit (wire interupted): would that prevent the motor turning at all?

[RogerH]

Hi Erik,

when in the parked position the end of the RED wire that is inside the motor cap is touching nothing - so there is no electric circuit.

When the motor turns, the red wire picks up on an earthed ring inside the motor cap and makes an extra earth.

 

If you now turn the wiper switch OFF the RED wire continues to be earthed and allows the motor to continue rotating UNTIL the red wire meets the break in the ring - Then it stops in the parked position.

 

Roger

[keith1948]

Hello Eric

When my wiper motor stopped working it was nothing to do with the motor. It was a loose fuse connection in the fuse box. Yes there was voltage at the motor but not enough current to move the wipers. Just cleaned the fuse connection and bent it in slightly and problem solved. On the TR4 wiring diagram, power goes from the fuse box to the voltage regulator. It then goes to the wiper motor via a double bullet connector which also feeds the indicators. This (on my RHD 4A) is located in the wiring loom above the steering column underneath the dash. Not easy to find but just locate a few green wires emerging from wiring loom going into the connector. Could be a loose connection here. If motor turns then I would check for loose connections or earth in wiring. If resistance is too high because of a loose connection (e.g loose fuse), then there will be insufficient power to turn the wiper motor.

Hope this helps.

I fitted a spare motor I had before I discovered loose fuse in fuse box. Been fine since (Wipers not the weather!)

Keith

[earckens]

Just come back from a repair session on the wiper motor.

 

Issue: no more wiping action when pulling the wiper button.

 

Roger, thank you for your input, it helped a lot.

 

Current status:

1. the red wire from the motor to the parking connection on the gearbox: the wire was not open circuit but the connection to the lug on the gearbox was open. I soldered the wire to the lug.

2. 12V does arrive from the green wire, the black wire is properly connected to ground; when I short the green/black wire lug to ground to motor works!

3. parking position works too, but the blades park in the middle of the windscreen!

 

Then I checked if the green/black wire was shorting to ground when the wiperswitch on the front panel is pulled: no short to ground.. So there is a interruption/bad connection in that circuit.

 

I have not had the time to investigate this cable routing because I would have to dismantle the fascia to get to this switch on the backside (no time right now). I could however feel, with blind checking by hand, that there are two wires connected to two adjacent switch lugs on that switch. A third lug, situated on the opposite side of this switch (still on the backside) was left unoccupied; I moved one of the two lugs (still blind handling) to this free lug, but no result so I replugged the wire to the original lug.

 

Keith1948's suggestion about the fusebox was tried and checked but since there is 12V arriving at the motor I doubt this would be an issue here.

 

Conclusion:

1. bad connection between the green/bmack wire and the facia switch

2. parking function is haywire

 

Any suggestions would be more than welcome!

 

Thks,

Erik

[RogerH]

Hi Erik,

the top of the wiper gearbox (where the red wire is connected) can be rotated to get the parking position of the blades sorted out.

Slacken the screws on the top of the wiper and rotate the round cap.

 

Roger

 

 

Edited December 26, 2016 by RogerH

[earckens]

Hi Erik,

the top of the wiper gearbox (where the red wire is connected) can be rotated to get the parking position of the blades sorted out.

Slacken the screws on the top of the wiper and rotate the round cap.

 

Roger

 

P1040360a.jpg

Hi Roger, your wiper motor and surroundings are so clean! I will take an example and try and emulate.

 

Which screws need to be slackened, I do not see any on the round cap?

 

Rgds,

Erik

Edited December 27, 2016 by earckens

[Grahamgl]

Hi Erik,

If you look at the picture of Roger's wiper motor you can see 4 small hexagon headed "screws". You need to slacken off, but not remove, the two adjacent to the dome cover, and then carefully rotate the dome cover to a point where the wiper arms come to rest in the right place on the screen when the wipers are turned off. Be careful of the arms "over wiping" at the bottom of the screen. When I did my car I removed the wiper arms and used masking tape wrapped around the spindle to act as markers.

Graham

[AlanT]

Before I go any further, I have re-built, repaired and sold over 100 of these now.

They have gone all over the world and many to pro-repairers.

 

These take a current of about 3A to run but nearer to 20A for a brief period to actually start.

 

Any kind of poor electrical joint will result in a stall, this is where power is applied, but the motor does not turn.

Any kind of poor lubrication, bent rack-wire etc will make a stall more likely.

 

Two-speed motors stall more easily on the FAST range and should always start in SLOW mode.

 

If you leave power applied to a stalled motor, then the armature will burn out, and it will become expensive to repair.

This takes a few minutes, but ONLY a few.

 

To run you only need 12V on terminal 2 and a ground on terminal 1. You can make direct temporary connections like this. This can pin-point that the wiring-loom and switch are maybe your real problem.

 

You dont need an earth on the body, you could cut off the red-wire and it will still go, these are ONLY for self parking.

 

The red-wire is joined directly to terminal 1 and so motor will also run if you short it to chassis.

 

If you send a PM with your email address I will respond with documents and photos that will help you to understand and restore this.

 

After 50 years they all need some kind of TLC, usually clean/relube/brushes as a minimum.

 

If the brushes wear down the commutator will be ruined, as shown in recent TR-Action article.

Don't do this. Armatures are RARE and not easily fixable.

Edited December 27, 2016 by AlanT

[earckens]

Hi Erik,

If you look at the picture of Roger's wiper motor you can see 4 small hexagon headed "screws". You need to slacken off, but not remove, the two adjacent to the dome cover, and then carefully rotate the dome cover to a point where the wiper arms come to rest in the right place on the screen when the wipers are turned off. Be careful of the arms "over wiping" at the bottom of the screen. When I did my car I removed the wiper arms and used masking tape wrapped around the spindle to act as markers.

Graham

Great! Thks for the info!

It will be however end of February before I can get back to this: we leave (sadly) for home tomorrow, so no TR4 the coming 8 weeks

Have great end of year celebrations,

Erik

[earckens]

Before I go any further, I have re-built, repaired and sold over 100 of these now.

They have gone all over the world and many to pro-repairers.

 

These take a current of about 3A to run but nearer to 20A for a brief period to actually start.

 

Any kind of poor electrical joint will result in a stall, this is where power is applied, but the motor does not turn.

Any kind of poor lubrication, bent rack-wire etc will make a stall more likely.

 

Two-speed motors stall more easily on the FAST range and should always start in SLOW mode.

 

If you leave power applied to a stalled motor, then the armature will burn out, and it will become expensive to repair.

This takes a few minutes, but ONLY a few.

 

To run you only need 12V on terminal 2 and a ground on terminal 1. You can make direct temporary connections like this. This can pin-point that the wiring-loom and switch are maybe your real problem.

 

You dont need an earth on the body, you could cut off the red-wire and it will still go, these are ONLY for self parking.

 

The red-wire is joined directly to terminal 1 and so motor will also run if you short it to chassis.

 

If you send a PM with your email address I will respond with documents and photos that will help you to understand and restore this.

 

After 50 years they all need some kind of TLC, usually clean/relube/brushes as a minimum.

 

If the brushes wear down the commutator will be ruined, as shown in recent TR-Action article.

Don't do this. Armatures are RARE and not easily fixable.

Alan, thks for this info! I pm'ed you,

Erik

[earckens]

Before I go any further, I have re-built, repaired and sold over 100 of these now.

They have gone all over the world and many to pro-repairers.

 

These take a current of about 3A to run but nearer to 20A for a brief period to actually start.

 

Any kind of poor electrical joint will result in a stall, this is where power is applied, but the motor does not turn.

Any kind of poor lubrication, bent rack-wire etc will make a stall more likely.

 

Two-speed motors stall more easily on the FAST range and should always start in SLOW mode.

 

If you leave power applied to a stalled motor, then the armature will burn out, and it will become expensive to repair.

This takes a few minutes, but ONLY a few.

 

To run you only need 12V on terminal 2 and a ground on terminal 1. You can make direct temporary connections like this. This can pin-point that the wiring-loom and switch are maybe your real problem.

 

You dont need an earth on the body, you could cut off the red-wire and it will still go, these are ONLY for self parking.

 

The red-wire is joined directly to terminal 1 and so motor will also run if you short it to chassis.

 

If you send a PM with your email address I will respond with documents and photos that will help you to understand and restore this.

 

After 50 years they all need some kind of TLC, usually clean/relube/brushes as a minimum.

 

If the brushes wear down the commutator will be ruined, as shown in recent TR-Action article.

Don't do this. Armatures are RARE and not easily fixable.

Hi Alan,

the issue is with the green/black wire from the motor to the cabin switch: when I short lug 1 to ground the motor runs.

Have a great day,

Erik

[AlanT]

This may be the switch. There is a topic on here where I dismantle and reassemble these switches.

 

You can find things on here using Google, this works much better than the forum search.

 

You do this as your Google search:

 

site:www.TR-register.co.uk wiper switch

[earckens]

This may be the switch. There is a topic on here where I dismantle and reassemble these switches.

 

You can find things on here using Google, this works much better than the forum search.

 

You do this as your Google search:

 

site:www.TR-register.co.uk wiper switch

Hi AlanT, I found this http://www.tr-register.co.uk/forums/index.php?/topic/55679-wiper-switch/most interesting piece, except that it is not clear from the picture which terminals are where. Do you have a drawing or something similar so it is clear which wire goes where? Since I have a TR4 it is one speed only, so it would be the green/black wiren and a ground wire (black?).

Thks!

Erik

[AlanT]

[earckens]

On the included picture I have terminals 1 and 2 swapped around, my mistake: must be green (12V) to 2 and green/black to 1.

 

The green/black must be switched to ground for the wiper to function. So I would think this wire goes to the dashoboard wiper switch which also has a ground wire connected.

 

 

But on your picture, AlanT, I see a red wire too???

 

Puzzled..

 

Erik

 

[AlanT]

This is the switch wiring for a two-speed 75568 TR4A motor.

 

There will be 12V to the green wire on the motor. This comes from the wiring loom via the ignition switch.

 

This switch grounds the red and brown wire from the motor.

 

It's often pretty hard, on an old motor, to identify the wire colours. And of course they do get altered.

[RAHTR4]

Erik,

 

It appears that things are getting confused because you have the wrong type of switch fitted to the car.

 

For operating a single speed wiper motor on a TR4, the switch should be a simple single pull on / off switch - Model PS7 - as shown below :

 

 

 

Let me know if you require anymore details or if you require a switch as I have a few spares.

 

Regards, Richard