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Old 31st August 2020, 08:08   #41
MarkS
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Quote:
Originally Posted by ADO282 View Post
When you look back over the half dozen or so cars where this has happened to, and in the case of the ones which were not burned out totally, it is evidenced by inspection of the plug, that the main power carrying contacts in the centre of the plug had green corrosion.
I think there potentially exists an unrecognised scenario, which may be causing the green corrosion on the main power carrying contacts.

Salt laden spray from the road sprays up onto the bottom of the engine fusebox, then runs down and into the 2 main power feed wires to the LSM main power contacts.
Once inside the wire, the salt laden water runs along the wires by capillary action, until it reaches the LSM, whereupon it runs into the LSM contacts, and INTO the LSM itself, causing corrosion, and high contact resistance. Switching the lights on causes heat buildup in the contacts, until the inevitable overheating and fire.

Vehicle age makes the problem become more prevalent.

We already know that capillary action causes corrosion within the wiring of the rear parking distance sensors.

I have already suffered from corrosion within the engine fusebox connections. Corrosion at the other end of two tubes (the wire insulation) seems inevitable, with time.

Thoughts ?
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Old 31st August 2020, 22:45   #42
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I presume from your observations that you have not got a cover underneath the engine compartment??If you have not got one, I suggest that if you fit one, your problem with what sounds like water and dirt being thrown up from the front wheels and the flow of air from under the car will cease to happen..
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Old 31st August 2020, 23:25   #43
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Capillary action of fluids down the inside of a wire is not unknown (Discovery 2 TD5's suffer with engine oil migrating down the loom and into the ECU ), but the distance involved in this scenario on a 75 is much greater.

As salt water would cause corrosion of the copper, I'd of thought that we'd be seeing problems of the wiring corroding away near the fuse box, long before the miniscule amounts that would make their way to the LSM, would cause any overheating ?
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Old 2nd September 2020, 19:18   #44
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Ive read all the posts on the problem and examined my 2004 MGZT se sport etc.and cant see the pictures relate to my car. It looks to be a complete moulding, I can see no "screws" that might be replaced by scrivits? Or am I just not "seeing" properly? Are face lifts different? Chris.S.
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Old 2nd September 2020, 20:47   #45
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Quote:
Quote:
Originally Posted by mileshawk56 View Post
Ive read all the posts on the problem and examined my 2004 MGZT se sport etc.and cant see the pictures relate to my car. It looks to be a complete moulding, I can see no "screws" that might be replaced by scrivits? Or am I just not "seeing" properly? Are face lifts different? Chris.S.
Hi Chris.
Facelift are the same as 1998 model in respect to where the LSM is and how it is fitted to the car.

Remove the two screws for the panel below steering.
1

2

Then pop the panel off.
3

4

This will give you access to the LSM
5

Remove the bottom screw.
6

Then the two top screws.
7

8

The light unit will then come forward.
9

You can unplug it by sliding the latch here below.
10

Replace the spire clips.
11

12

13

Once the spire clips have been removed replace with scrivets.
14

15

16

Offer the LSM back up to the scrivets and screw them in.
17

18

19

Replace spires on the panel too for scrivets.
20

Fit the lower panel back with normal screws these will soon pull out if needed.
21

22

The LSM can be taken apart and cleaned of dust also checked for corrosion.
23

24

25

hope the photos help

Arctic
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Old 2nd September 2020, 21:29   #46
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I took my LSM out again yesterday to give it another blow-through with an airline, to remove any dust. Whilst looking up under the dash, I noticed a paper build sticker that was attached directly above the LSM, and due to old age, was now starting to peel off & hang down (Arctic's pictures also show it).

I'm guessing that this can't be ideal, especially if if were to find it's way through one of the venting slots in the LSM, and touch something hot....?

Just wondering if this could be a possible source of initial ignition, leading to combustion of the foam dash moulding ??

Having removed all of my sticker, thoughts then went to a shaped metal heat shield or box, to help contain the LSM ???
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Old 2nd September 2020, 21:33   #47
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A couple of years ago I briefly had a zt t that I had to fix before selling on.
Once fixed it was given a wash, when I was drying it off I opened the drivers door and spotted a water trail on the side trim for the bonnet and boot switch.
Later that day I bought some Captain tolleys creeping crack cure and poured it about 6 inches back from the roof trim, lifting the edge of the windscreen rubber also to allow it to find an escape, eventually dripping slowly on the floor.
No trace of water inside the car a day later when I poured water around that area and to my knowledge there was never another problem with water ingress in that area.
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