Author Topic: Sluggish wiper motor - and it's not the earth! (Read 13583 times)

JohnFol · « **on:** December 04, 2020, 05:43:04 PM »

Morning all, about to tackle the slow wipers and noticed I get 10.6v between the block connector (disconnected from wiper motor) and battery -ve terminal. Battery is new, fully charged and connected to a trickle charger so somewhere between battery and block connector I'm dropping a few volts.
More than capable of tracing the wires through the fuse box, switches etc. but hoping there are some well known places to look first.
Any thoughts appreciated

peteracs · « **Reply #1 on:** December 04, 2020, 05:55:34 PM »

Hi John

That is an interesting reading. Sorry no idea what reading you should get, but there are a bunch of wires going to the wiper to give the parking etc, can you say what voltage is on which wire and what switch position you have it on?

Peter

HFStuart · « **Reply #2 on:** December 04, 2020, 10:22:08 PM »

I've got a feeling that the wiper power goes through the column stalk control and through the two speed switch on the dash. You could trace them and see what voltage you've got at each point or you could just rewire it with a relay or two. Perhaps check the motor with a direct supply first to make sure it's not shagged.

JohnFol · « **Reply #3 on:** December 04, 2020, 10:34:56 PM »

I have a 12v supply on my bench so will run a few wires and see.

Thanks for the pointers regards the routing. Haynes has its uses but nothing beats a bit of experience.

Nigel · « **Reply #4 on:** December 04, 2020, 11:38:35 PM »

John,
Electrics acknowledged, but it's worth
removing the assembly from the car. Easy job but fiddly.

The spindles can get very tight and are held together by a circlip on each. be careful,
they tend to fly, never to be seen again. Lithium or similar grease is best. Once you've disconnected the
motor from the arms you'll be able to feel if it's tight or not.

Regards, Nigel

peteracs · « **Reply #5 on:** December 05, 2020, 10:13:12 AM »

Hi John

I know your initial concern was with the motor disconnected and hence electrical, but I would check the mechanism for being partially seized. The main culprits as mentioned above are the spindles which have the wiper blades attached.

Peter

JohnFol · « **Reply #6 on:** December 05, 2020, 05:35:19 PM »

Thanks all. Backlog of jobs and a few days over xmas getting more full by the day.

JohnFol · « **Reply #7 on:** January 09, 2021, 03:08:07 PM »

Ok, time allows for some dis-assembly.

I've traced out the wiring and see there are 2 devices between switch and motor. One is a "windscreen wiper motor change-over switch" and the other is the "intermittance device". Wiring looks simple but finding them on the car is another story. Any pointers?

Nigel · « **Reply #8 on:** April 20, 2022, 10:18:33 PM »

Hi John,
Old topic I know, but did you find the issue with your
sluggish wipers?
I have fitted a relay [as per Eric's suggestion] on the 2nd speed,and it's running at crazy brilliant speed,
but the first speed is hopeless. I attempted fitting an additional relay to this, but it
didn't work.

Regards, Nigel

john930 · « **Reply #9 on:** April 21, 2022, 09:20:09 AM »

I was only getting about 10v to the wipers, so I fitted two relays one for low speed and one for high speed and problem solved !

JohnFol · « **Reply #10 on:** April 21, 2022, 09:46:49 AM »

John930, I have added a box that has relays for starter and fan with capacity for 2 more however I'm being selective on what I add in (as head lights are a contender). My logic was if I could get 12v to the motor then perhaps the issue would resolve itself. Working back I found only 10v at the fuse box which seems to be common.

So new ignition switch, battery, battery leads (+ve and -ve), new cables to fuse box, cleaned connectors, new earth straps at front and so on. I now get a better voltage at the fuse box, but it seems to "climb" up to 12v suggesting still an issue somewhere. Gut feeling is a poor connector somewhere in the spaghetti.

Nigel not fixed yet but trying a different line of investigation to adding in a relay. More than happy to keep the discussion alive and share what I find

Nigel · « **Reply #11 on:** April 21, 2022, 05:36:33 PM »

John930,

I clearly did it wrong on the 1st speed. If possible, can you tell me which colour wire on the motor
was the relay for this.

Much appreciated,
Nigel

JohnFol · « **Reply #12 on:** June 28, 2022, 02:05:26 PM »

This is what I have. Of course that doesn't mean too much

JohnFol · « **Reply #13 on:** June 28, 2022, 02:07:26 PM »

BTW Nigel these were all relative to earth. Not sure of the impact of the Change Over Switch, but I think it answers your question

Nigel · « **Reply #14 on:** June 28, 2022, 06:52:23 PM »

John,
Thanks for that.
At some stage earlier I managed, with some cleaning of fusebox connectors,
to get just more than 11v at the column connector. I'm glad I did as it
poured down on the way to the French meet.

I will be revisiting this a bit later,after more pressing jobs.

Cheers, Nigel

peteracs · « **Reply #15 on:** June 28, 2022, 10:00:49 PM »

Quote from: JohnFol on June 28, 2022, 02:05:26 PM

This is what I have. Of course that doesn't mean too much

Hi John

Thanks for that saves me some head scratching when I retire the HPE

Peter

JohnFol · « **Reply #16 on:** April 17, 2023, 01:02:44 PM »

Hi Nigel, I've been motivated by Peter's other post to revisit my wipers.

One thing I found today is disconnecting wiper motor and I now get 12v give or take. Lifting wiper blades off windscreen and slow speed is acceptable. Blades on screen and it's a crawl with voltage down to 8.

99% sure the spring tension on wiper arm is way to high, so motor struggling to overcome resistance of wiper blade on screen.

WestonE · « **Reply #17 on:** April 17, 2023, 02:31:43 PM »

Hi John

Have you stripped cleaned and re-greased the rack spindles? If you disconnect the motor connection to the rack (mark where it fits on the spindle) and lift the wipers from the screen how freely does the rack move? They can get very stiff and working through with a strip clean and re-grease can transform it. NB waterproof cycle grease.

Eric

JohnFol · « **Reply #18 on:** April 17, 2023, 03:02:36 PM »

On the list and I noticed the crank under the scuttle in middle of car just nudges the air flap as it rotates. Still feel the springs are excessively strong when compared to other cars . .. Unfortunately not been able to source any replacements..

Nigel · « **Reply #19 on:** April 17, 2023, 07:49:18 PM »

Hi John,
I've never noticed the mechanism fouling the air flap, it may be that
your flap cable needs adjusting, or, that the mechanism is bent out of shape a bit.

In my experience the wiper motor is well up to the task provided it gets full
voltage, and that is our collective conundrum!
As I mentioned elsewhere, I'm getting 10.4-11.4v at the fuse, this with engine running
and battery voltage at 14.2v, so there's clearly an issue. Fitting a relay on
the 2nd speed gave me a really fast wipe, wiring the 1st speed with a relay was a failure because,
I think, the intermittent relay is a major part of the 1st speed circuit, causing conflicts.

Incidentally, my indicators are also weak and slow, the dash tell-tales are almost invisible, these are
fed from the same fused circuit, so I'm hoping my repairs will fix this as well.

I'm now in the slow process of doing a total rewire of the wipers, bypassing the fuse box and
its horrible internals.

Erics point on the spindles is a vital step in the fault-finding. I don't think you need to
focus on the arm spring strength right now, mine are quite strong as well.

Nigel

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Author Topic: Sluggish wiper motor - and it's not the earth! (Read 13583 times)