75ZT Community

Ed3 wrote:Thanks Steve. Today there is more heavy rain so thanks for the warning.

I am confused by what I am finding. I went to start with the rear drains in the saloon boot but I am puzzled the drain pipe connections look brand new and clean.

A Rover 75 owner had same problem here in 2013 and gave up trying to fix it

https://www.mg-rover.org/threads/water- ... lp.587690/

The driver side rear passenger carpet is already unhooked free from by the sill by a previous owner and I soon had a gallon of water in my wet vacuum cleaner. Water keeps reappearing from under the carpet.

I put my old style square Thule Universal roof bars with a 6' x 4' (1.8m x 1.5m) tarp wrapped around the bars to keep rain off the sunroof.

Hi Ed.
Don't be that chap above, sunroof leak drains can and have been solved with great success it's just a case of time and effort.

I presume you have a saloon so the rear ones are easy accessible, mine was a Tourer which is even more work to reach the rear drains, but most of the time it's the fronts that cause the problem, anyways pull out the tube and you will see it is only just inside by about 5/7mm which is not good from factory.
[url=%URL_VIEWER_PREVIEW%][/url]A

[url=%URL_VIEWER_PREVIEW%][/url]B

[url=%URL_VIEWER_PREVIEW%][/url]C

[url=%URL_VIEWER_PREVIEW%][/url]D

[url=%URL_VIEWER_PREVIEW%][/url]E

The same goes for the front which are the real problem, once water gets in it goes under the carpet, and because of the sponge it can take years before the water shows above the surface of the carpet, usually first sign is just below the seat belt anchorage area little dip.
[url=%URL_VIEWER_PREVIEW%][/url]1

[url=%URL_VIEWER_PREVIEW%][/url]2

[url=%URL_VIEWER_PREVIEW%][/url]3

With connectors i used from Halfords.
[url=%URL_VIEWER_PREVIEW%][/url]4

[url=%URL_VIEWER_PREVIEW%][/url]5

You can use tip of sealant which would do the same job, but the ones i used have barbs so they hold in.

The water by then because of the floor pan design it flows to the rear and eventually fill all the floor pan.
You will also need to peel back the front wheel arch liner and cut a bit off the sunroof outlet tubes as here below.
[url=%URL_VIEWER_PREVIEW%][/url]6

[url=%URL_VIEWER_PREVIEW%][/url]7

[url=%URL_VIEWER_PREVIEW%][/url]8

[url=%URL_VIEWER_PREVIEW%][/url]9

[url=%URL_VIEWER_PREVIEW%][/url]10

Don't give up at the moment clean what you can out without removing the carpets then come summer get them out, and dry it out completely, or if you have a carpet from another car replace it with that.

Thanks Steve, On my previous saloon (no sunroof) I had no option but to take the carpet/seats out and clean all up but did so with the car off road for a few months.

On this recent saloon the past owners have sued those Halfords white drain pipe connectors in the boot and so I am suspect they will have done the usual sunroof clean the tubes and the rain water leak is a little more unusual such as possibly the panel seams (drivers side of car to roof) leaking to only to the drivers side rear footwell. There is constant heavy rain here so progress is slowed

UPDATE - with water levels inside the car going down with regular wet vacuum the electrics seem normal (but I still disconnect the battery in case). SO If I can stop the leaks all will be ok in due course.

And this might explain the electrical issues. Leaking front sunroof drains, on the drivers side can get water into both the light switch module, and the immobiliser. Immo can be seen in one of Steves pictures. It's really important to check, especially the light switch, as water in there can cause it to 'overheat' which you REALLY don't want. Do that especially the light switch, before connecting the battery again.

Thanks Duncan, First few days of less wet weather.

With a tarp roof rack to keep the rain off the roof and vacuum cleaning the rain water from the o/s rear passenger footwell it looks like electrics become normal with there not being a flood in the floor and no more water entering. From feeling which carpets are wetter I am guessing the water is running down the drivers side B pillar (between the front & rear doors).

I used the DMGRS white (curtain hanger style) wire probe to push into the front drains and got 64 inches down the passenger side front drain but only 54 inches down the drivers side front drain and it stops. I am not sure if it is snagging on a joint/bend or a blockage???

I cant find the rear drains as yet as not easy to see with my tarp roof rack.

I am trying to be careful with not wasting effort as I imagine I may need to take both carpet and headlining out to fix this one. Because on a 75 CDTi with only 86k miles and wooden steering wheel model previous owners will have tried and failed.

Just tried a hose pipe on the front drains. The near side drain (where the probe goes down 64 inches) has a clear flow of water. The drivers side where the problem only goes down 54 inches had a trickle of water but after the test I ended up vacuuming over a gallon out of the rear passenger footwell. So the front drain not flowing correctly can send water to the rear passenger footwell.

As yet I cant find the rear drain holes at the sunroof to test them.

I am trying to upload a photo of the driver's footwell showing where the drain should be top left by the light blue tape, but it is hidden behind. This all looks confusing? as if the previous owner had a go and gave up?

Just found this video below which someone as done but not properly, do not make the same mistake, the outlet tube behind the wheel arch liner must be cut off for this mod to be successful
https://youtu.be/jzukGsCWH94?si=reZLn6frZUXM1i1w

Thanks Steve. I have been watching that youtube.
UPDATE- now we have sunny days -attempted a temporary fix

I carefully poured a test of half a litre of hot water with washing up liquid into each front side of sunroof drains. Patches of water arrived on the ground under all sunroof drain exits -except for the driver's side front sunroof drain.

High in the driver's side footwell I have found the drain pipe totally discioneted hanging above some electrics.

Attempt at temporary fix - I plugged the front drivers side drain hole at the sunroof hoping a temporary 25% loss of drain holes will not be too much of a problem. Aftermarket universal windscreen washer pipe fits nicely into a clean sunroof drain hole as a plug using around 12 inches of washer pipe fed down the problem drain hole.

Wipers started going by themselves again and I don't know if wires in the drivers footwell need to dry or .....

Right, so the water is going down the drivers A pillar somewhere. PLEASE check for water in the light switch connector. Today. Check the immobiliser as well, but check the lightswitch. It's two screws for the panel, and three for the switch. Water in the light switch needs to be fixed NOW even if it isn't whats causing your wiper problems.

I have been parked in a safe area with the battery lead off doors unlocked. I have again vacuumed all excess water. And put tissues and duster high under the dash to make sure all is dry.

But since I did the test by pouring a jug of water into the sunroof drain the electrical system is always doing it's own thing.

Because the drivers front drain is fully disconnected, the half litre of test water would have poured over the white immobiliser unit. It looks to me from photos online as if the socket for the immobiliser will trap moisture?
https://www.ebay.co.uk/itm/277781850597 ... R9Dj46qhZw
And with late night test drives it seems the mileage and the dash warning above the mileage stays on after parking the car (unlocked\. The alarm sounds if I lock the car and so I will not. And the immobilser light does strange things.
I always struggle to know how to unplug these sorts of plastic connectors plugs on the Rover 75. Any tips?
Should I swap the immobilser unit from another Rover 75 facelift CDTi to test that? Or is the immobiliser programmed for each individual car?

Ed3 wrote:I have been parked in a safe area with the battery lead off doors unlocked. I have again vacuumed all excess water. And put tissues and duster high under the dash to make sure all is dry.

But since I did the test by pouring a jug of water into the sunroof drain the electrical system is always doing it's own thing.

Because the drivers front drain is fully disconnected, the half litre of test water would have poured over the white immobiliser unit. It looks to me from photos online as if the socket for the immobiliser will trap moisture?
https://www.ebay.co.uk/itm/277781850597 ... R9Dj46qhZw
And with late night test drives it seems the mileage and the dash warning above the mileage stays on after parking the car (unlocked\. The alarm sounds if I lock the car and so I will not. And the immobilser light does strange things.

I always struggle to know how to unplug these sorts of plastic connectors plugs on the Rover 75. Any tips?
Should I swap the immobilser unit from another Rover 75 facelift CDTi to test that? Or is the immobiliser programmed for each individual car?

Hi ED.
You can't just unplug the white EWS (Engine immobiliser (EWS from the German, Elektronik WegfahrSicherung)) and fit another from any car, it has to be coded to your car by a T4 (Testbook version 4.Computer Diagnostic System) you would have to send your old ECU (Engine Control Unit) and EWS off to some like Marina Brian, or Big Russ to sort out for you.

Thanks Steve,
On the web posts for all types of cars it seems to suggest wet wiring is not unusual and they use a spray that is designed for that? The posts were in the USA. I wonder if members here have preferences for which spray is best?
I am now getting more used to spotting when the electrics are going wrong and the early warning is the mileage reading on the dash lights up when the key is away from the car.
I did a late night drive with air con hot to try to help dry things and I am not sure if it is slightly better today.
Thanks Ed

Have you checked the light switch, yet?

Thanks Duncan, I put my had around the back of it and it felt very clean and very dry. The end of the disconnected drain pipe is close to the bulk head and the feel is a there has been muddy dirty leak. So with the light switch a few inches away and feeling very clean i though it was ok?

And the only symptoms of electrics 'doing as they wish' - are wipers on when car parked, alarm if try to lock the car, the mileage display coming alive without the key being near, the warning of doors open coming alive without the key near and the immobiliser light flashing. So I am thinking the plug/socket of the immobiliser is affected but not the clean light switch

Ed3 wrote:Thanks Duncan, I put my had around the back of it and it felt very clean and very dry. The end of the disconnected drain pipe is close to the bulk head and the feel is a there has been muddy dirty leak. So with the light switch a few inches away and feeling very clean i though it was ok?

And the only symptoms of electrics 'doing as they wish' - are wipers on when car parked, alarm if try to lock the car, the mileage display coming alive without the key being near, the warning of doors open coming alive without the key near and the immobiliser light flashing. So I am thinking the plug/socket of the immobiliser is affected but not the clean light switch

Please, check it anyway. If there's water in the connector (it can run down the wiring) you may not spot it without pulling the switch out (3 screws) and opening the connector. The connector is pretty easy to open. There's like a saddle. It needs to be folded away from where it is, and the connecter eases its way out. Theres a tab to press, to do it. Water in that connector can cause things to 'overheat' and the fuses won't prevent it.

Thanks Duncan, I will check that.
Update as in photos of dirty contacts in the immobiliser and the plug that goes into it. On refitting the plug I had to push hard a couple of extra times to get the connection so that the starter motor would work. Will try to clean these contacts now and have a neighbour who is ex BT telephones so hoping his experience with cleaning contacts will be good. .

Yep. the immobiliser connector is showing clear signs of water. the green and brown colours. It can get to a state where you can't set the alarm, because the cars system thinks the key is still in the lock. That is when the permanent feed to the immobiliser is lost because of the corrosion in your picture. Not saying it has come to that yet in your case but it could. Now back to potential water in the light switch module: please, PLEASE, check as soon as you can. The problem is very likely the water in the immobilser connection, but if there is water in the light switch module the outcome can be disaster (major overheating of critical electronics).

This morning my neighbour who is ex BT brought a basic spray cleaner for electrical contacts. He said the immobilser socket pins are too fragile to rub to clean and said to only spray the immobiliser pins and the wiring loom socket and push together and pull apart a number of times to clean.

The white immobiliser box opens up easily and the circuit board slides out. My neighbour said although the edges are discoloured the circuit board is covered during manufacture in a varnish of sorts that protects it.

I cant add photos are they are too large for the website limit, so I add the only one I could cut down showing the circuit board out of the white box.

So in dry weather (and only the carpet underlay still damp)- after doing as simple as spray cleaner on the immobiliser contacts and wiring loom plug and plugging in and apart a few times the initial result is good - with the battery is connected all works normally for the last hour. When wipers would go or dash would light up after 10 minutes previously

Yes, the immobilser board is covered in stuff called conformal coating, and the board itself is pretty well protected. It's the connector that suffers (though water can creep underneath the coating). I know of at least 2, where the permanent life pin corroded away. It's worth knowing that the terminals on the grey box, are actually steel pins plated with tin. That means that they actually rust away. Did I ask if you have checked the light switch?

Where do we check on the light switch module when all is dry like at the moment? there are photos of an ebay one here and not sure where to check when all is dry?
https://www.ebay.co.uk/itm/388538109334 ... JG7ZVV110P

Also here it is suggetsed to renew the immobiliser? And has good photos of the drain pipe https://www.ebay.co.uk/itm/194376080084

Ed.
Remove the plastic plate from under the steering wheel a few screws and it pops off.
[url=%URL_VIEWER_PREVIEW%][/url]1

[url=%URL_VIEWER_PREVIEW%][/url]2

Once removed you have access to the light switch which we refer to LSM (Light Switch Module) three screws tow either side one at the bottom.
[url=%URL_VIEWER_PREVIEW%][/url]3

[url=%URL_VIEWER_PREVIEW%][/url]4

It will then pull forward so you can unplug the wiring from it, which is a lift over toggle.
[url=%URL_VIEWER_PREVIEW%][/url]5

These are the different types depending on what lights you have on your car.
[url=%URL_VIEWER_PREVIEW%][/url]6

First check the pins and the plug for corrosion
[url=%URL_VIEWER_PREVIEW%][/url]7

To take the cover off and check the inside for corrosion is easy only a few tags to tease open and the front will slide out be careful as there is a ribbon so don't pull hard, this to can be undone.
[url=%URL_VIEWER_PREVIEW%][/url]8

[url=%URL_VIEWER_PREVIEW%][/url]9

[url=%URL_VIEWER_PREVIEW%][/url]10

[url=%URL_VIEWER_PREVIEW%][/url]11

[url=%URL_VIEWER_PREVIEW%][/url]12

[url=%URL_VIEWER_PREVIEW%][/url]13

[url=%URL_VIEWER_PREVIEW%][/url]14

Also don't over think the sunroof connectors too much you can use these below, ends off silicone tubes, the pen represents the sunroof tube.
[url=%URL_VIEWER_PREVIEW%][/url]15

[url=%URL_VIEWER_PREVIEW%][/url]16

The job is more time consuming than hard to do.