Go Back   The 75 and ZT Owners Club Forums > The 75 and ZT Owners Club Forums > Technical Help Forum
Register FAQ Image Gallery Members List Calendar Mark Forums Read
Notices

Reply
 
Thread Tools Display Modes
Old 10th June 2022, 06:31   #1
Southcoaster
Newbie
 
MG ZT-T

Join Date: Feb 2022
Location: Eastbourne
Posts: 16
Thanks: 4
Thanked 8 Times in 4 Posts
Default Screenwash sWitch

I finally got around to changing the screenwash pump yesterday, on the ZT-T I bought from BigAde. New pump is visually very similar to old, with one electrical and 2 hose connections, and I now have 4 fine jets onto the front screen. The problem now is that I still get these just 4 fine jets when operating the rear washer switch, and nothing to the rear!


As there are only 2 wires to the pump, how does it know which way to send the water? Or, if it always sends to both front and rear, why are there 2 separate switches?
Southcoaster is offline   Reply With Quote
Old 10th June 2022, 07:12   #2
SD1too
Doesn't do things by halves
 
SD1too's Avatar
 
Rover 75 2.5 Connoisseur Auto (1999) Dealer launch model.

Join Date: Mar 2007
Location: Former Middlesex
Posts: 20,265
Thanks: 1,587
Thanked 3,749 Times in 3,181 Posts
Default

Hi Peter,

The ZT-T washer wiring diagram is confusing to say the least. The sub-loom from the rear wash/wipe controls isn't shown at all!

I'd like to see this if you fancy a day trip to London. But first, is there absolutely definitely only one pump in the reservoir (my SD1 had two, one above the other)?

Simon
__________________
"Whatever is rightly done, however humble, is noble."
Sir Henry Royce.

Last edited by SD1too; 10th June 2022 at 09:02.. Reason: After studying the wiring diagrams
SD1too is offline   Reply With Quote
Old 10th June 2022, 18:30   #3
Southcoaster
Newbie
 
MG ZT-T

Join Date: Feb 2022
Location: Eastbourne
Posts: 16
Thanks: 4
Thanked 8 Times in 4 Posts
Default

I haven't looked for the diagram as yet, not sure it would help. I did idly wonder if the pump would spin either way depending if voltage was reversed, but the pipes are in a definite tee off the pump. I believe models with headlamp washers have a second pump, and the wiring is there for that. I can't even see that back-pressure from a blocked rear nozzle would cause the fluid to go to the front. I hope someone knows how this set-up works or can tell me the pump (supplied by the PO) is wrong.


As for day trips to London, I have a short walk to the big metal cars than run in queues thanks, but it's lovely down here on the South Coast!
Southcoaster is offline   Reply With Quote
Old 10th June 2022, 19:58   #4
daveo138
Gets stuck in
 
daveo138's Avatar
 
Rover 75 Tourer

Join Date: Mar 2022
Location: Chesterfield
Posts: 616
Thanks: 206
Thanked 69 Times in 53 Posts
Default

The Haynes wiring diagram is pretty useless, as it only shows one switch.

This is my pump, which has just two wires going to it and two pipes coming from it...



I would imagine that for the rear washer, the polarity is reversed and the motor runs in the opposite direction. If yours doesn't, it looks like it's either faulty, or the wrong pump.

Can you check with a meter to see if the polarity is reversed?
daveo138 is offline   Reply With Quote
Old 10th June 2022, 20:11   #5
SD1too
Doesn't do things by halves
 
SD1too's Avatar
 
Rover 75 2.5 Connoisseur Auto (1999) Dealer launch model.

Join Date: Mar 2007
Location: Former Middlesex
Posts: 20,265
Thanks: 1,587
Thanked 3,749 Times in 3,181 Posts
Default

Quote:
Originally Posted by daveo138 View Post
I would imagine that for the rear washer, the polarity is reversed and the motor runs in the opposite direction.
What's your thinking Dave? If the motor ran backwards, wouldn't it pump water from the tubes back into the reservoir?

What are the other two wires in your photo?

Simon
__________________
"Whatever is rightly done, however humble, is noble."
Sir Henry Royce.
SD1too is offline   Reply With Quote
Old 10th June 2022, 20:18   #6
daveo138
Gets stuck in
 
daveo138's Avatar
 
Rover 75 Tourer

Join Date: Mar 2022
Location: Chesterfield
Posts: 616
Thanks: 206
Thanked 69 Times in 53 Posts
Default

I'm thinking that there's a valve to direct the fluid, depending on which way it's running.

The other two wires are for the level sensor.
daveo138 is offline   Reply With Quote
Old 10th June 2022, 23:10   #7
BigRuss
Premium Trader
 
BigRuss's Avatar
 
75 CDT Tourer,2.5 Launch Saloon, Omipro MG/Rover (T4)

Join Date: Jul 2007
Location: Liversedge, West Yorkshire
Posts: 5,405
Thanks: 1,105
Thanked 1,340 Times in 661 Posts
Default

Yes the pump reverses direction for the rear washer, the valve controls which outlet is supplied

Russ
__________________


Replacement Key Service
http://https://the75andztclub.co.uk/...d.php?t=244732
Full T4 Testbook diagnostics available.
Diesel ECU repair and replacement.
Options enabled or disabled as required.
Diesel X-Power 135 and 160bhp, Rover 1.8T 150 to 160
MG 160 V6 to 177 upgrades available
P.M. for details.

Last edited by BigRuss; 10th June 2022 at 23:13..
BigRuss is offline   Reply With Quote
Old 11th June 2022, 07:10   #8
SD1too
Doesn't do things by halves
 
SD1too's Avatar
 
Rover 75 2.5 Connoisseur Auto (1999) Dealer launch model.

Join Date: Mar 2007
Location: Former Middlesex
Posts: 20,265
Thanks: 1,587
Thanked 3,749 Times in 3,181 Posts
Default

Quote:
Originally Posted by daveo138 View Post
Can you check with a meter to see if the polarity is reversed?
Peter, could you report back on Dave's suggestion please?

Simon
__________________
"Whatever is rightly done, however humble, is noble."
Sir Henry Royce.
SD1too is offline   Reply With Quote
Old 11th June 2022, 10:08   #9
Southcoaster
Newbie
 
MG ZT-T

Join Date: Feb 2022
Location: Eastbourne
Posts: 16
Thanks: 4
Thanked 8 Times in 4 Posts
Default

Quote:
Originally Posted by BigRuss View Post
Yes the pump reverses direction for the rear washer, the valve controls which outlet is supplied
Russ

Thank you.



Quote:
Originally Posted by SD1too View Post
Peter, could you report back on Dave's suggestion please?
Simon

It's the next job on my list now, when I can get out there. I guess I need to figure out whether the fault lies with the supply, motor or valve.
Southcoaster is offline   Reply With Quote
Old 11th June 2022, 15:29   #10
SD1too
Doesn't do things by halves
 
SD1too's Avatar
 
Rover 75 2.5 Connoisseur Auto (1999) Dealer launch model.

Join Date: Mar 2007
Location: Former Middlesex
Posts: 20,265
Thanks: 1,587
Thanked 3,749 Times in 3,181 Posts
Default

Quote:
Originally Posted by BigRuss View Post
Yes the pump reverses direction for the rear washer, the valve controls which outlet is supplied.
How does this system work then Russ?

Simon
__________________
"Whatever is rightly done, however humble, is noble."
Sir Henry Royce.
SD1too is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT. The time now is 13:25.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright © 2006-2023, The Rover 75 & MG ZT Owners Club Ltd