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 Search Today's Posts Mark Forums Read
Notices

Reply
 
Thread Tools Display Modes
Old 27th July 2020, 08:31   #1
Odd Job
My Gremlin got wet!
 
Odd Job's Avatar
 
MG ZT 2.0 cdti

Join Date: Aug 2019
Location: Derby
Posts: 695
Thanks: 227
Thanked 157 Times in 116 Posts
Default Auto Dimming Rear View Mirror

Hi all,

I wonder if anyone has experienced this regarding the auto dimming rear view mirror.
This is the first car I've owned with one, and I'm not sure if I've got a problem, or if this is what they do!
I've not not driven it much at night, but on Friday I was.

Basically, does it work. YES. It works.
Does it work all the time, or rather when I need it to work. NO

I've noticed that a car with "standard" non dazzling headlights will cause it to darken.
But, I've noticed that if a vehicle has these more modern "turn the road into daylight" headlights, the damn thing wont operate!

I have a theory, I may be well off the mark, but it goes like this.
The mirror shouldn't darken in actual daylight.
So, if the car behind headlights have a beam which is in the daylight spectrum, it fools the sensor and so wont darken.
Does this sound possible?

Many thanks for any ideas and help!
__________________
Ö.And the latest thing to break is.....

The thermostat
The brake light switch ( brake light witch I call it! )
Central locking mind of it's own.
No air-con ( I know what the problem is though )
The Maf
Number plate light circuit board
O/S/F top suspension mounting
The Clutch master cylinder push rod - just snapped
The Radio / CD player - just died.
The internal boot release switch ( witch ) mind of its own.
Throttle Potentiometer - just failed
### MG STANDS FOR "MY GREMLIN" !!!
Odd Job is offline   Reply With Quote
Old 27th July 2020, 09:18   #2
HarryM1BYT
This is my second home
 
HarryM1BYT's Avatar
 
75 Contemporary SE Mk II 2004 Man. Sal. CDTi 135ps, FBH on red diesel, WinCE6 DD

Join Date: May 2010
Location: Garforth, W. Yorks
Posts: 16,962
Thanks: 2,137
Thanked 1,922 Times in 1,486 Posts
Default

Quote:
Originally Posted by Odd Job View Post
But, I've noticed that if a vehicle has these more modern "turn the road into daylight" headlights, the damn thing wont operate!

I have a theory, I may be well off the mark, but it goes like this.
The mirror shouldn't darken in actual daylight.
So, if the car behind headlights have a beam which is in the daylight spectrum, it fools the sensor and so wont darken.
Does this sound possible?

Many thanks for any ideas and help!
I haven't noticed, no, but....

Modern headlights have a much sharper cut off of the upper part of the beam, than older halogen designs and if they are dipped behind you, they probably would not appear bright enough to your mirror so as to cause it to dim.

A problem I do notice when reversing out of my dark garage, out into daylight, is that the mirror sees darkness ahead, bright behind and dims the mirror. A thumb over the sensor, bring it back to undimmed.
__________________
Harry

How To's and items I offer for free, or just to cover the cost of my expenses...

http://www.the75andztclub.co.uk/foru...40#post1764540

Fix a poor handbrake; DIY ABS diagnostic unit; Loan of the spanner needed to change the CDT belts; free OBD diagnostics +MAF; Correct Bosch MAF cheap; DVB-T install in an ex-hi-line system; DD install with a HK amp; FBH servicing.

I've taken a vow of poverty. To annoy me, send money.
HarryM1BYT is offline   Reply With Quote
Old 27th July 2020, 09:28   #3
Odd Job
My Gremlin got wet!
 
Odd Job's Avatar
 
MG ZT 2.0 cdti

Join Date: Aug 2019
Location: Derby
Posts: 695
Thanks: 227
Thanked 157 Times in 116 Posts
Default

OK , many thanks.

I did notice it a few times, ( not dimming ) perhaps it's because I wear glasses that makes me more susceptible to being dazzled?

So, that leads me to ask another question.
Can I fit a non-auto dimming mirror without messing with the rain sensor?
__________________
Ö.And the latest thing to break is.....

The thermostat
The brake light switch ( brake light witch I call it! )
Central locking mind of it's own.
No air-con ( I know what the problem is though )
The Maf
Number plate light circuit board
O/S/F top suspension mounting
The Clutch master cylinder push rod - just snapped
The Radio / CD player - just died.
The internal boot release switch ( witch ) mind of its own.
Throttle Potentiometer - just failed
### MG STANDS FOR "MY GREMLIN" !!!
Odd Job is offline   Reply With Quote
Old 27th July 2020, 09:53   #4
wullie480
This is my second home
 
Insignia VX-Line & Insignia tourer

Join Date: Dec 2010
Location: Bunnyville
Posts: 5,084
Thanks: 517
Thanked 981 Times in 754 Posts
Default

Quote:
Originally Posted by Odd Job View Post
OK , many thanks.

I did notice it a few times, ( not dimming ) perhaps it's because I wear glasses that makes me more susceptible to being dazzled?

So, that leads me to ask another question.
Can I fit a non-auto dimming mirror without messing with the rain sensor?

Instead of swapping the mirror to a non auto dip you could just unplug the current one to prevent it working that way it all looks the same and saves you buying a mirror.


Sent from my iPhone using Tapatalk
wullie480 is offline   Reply With Quote
Old 27th July 2020, 09:57   #5
Odd Job
My Gremlin got wet!
 
Odd Job's Avatar
 
MG ZT 2.0 cdti

Join Date: Aug 2019
Location: Derby
Posts: 695
Thanks: 227
Thanked 157 Times in 116 Posts
Default

Stupid question coming up, but I really dont know the answer!
So, when the unit is unplugged, it's dark all the time?
__________________
Ö.And the latest thing to break is.....

The thermostat
The brake light switch ( brake light witch I call it! )
Central locking mind of it's own.
No air-con ( I know what the problem is though )
The Maf
Number plate light circuit board
O/S/F top suspension mounting
The Clutch master cylinder push rod - just snapped
The Radio / CD player - just died.
The internal boot release switch ( witch ) mind of its own.
Throttle Potentiometer - just failed
### MG STANDS FOR "MY GREMLIN" !!!
Odd Job is offline   Reply With Quote
Old 27th July 2020, 10:05   #6
wullie480
This is my second home
 
Insignia VX-Line & Insignia tourer

Join Date: Dec 2010
Location: Bunnyville
Posts: 5,084
Thanks: 517
Thanked 981 Times in 754 Posts
Default

Quote:
Originally Posted by Odd Job View Post
Stupid question coming up, but I really dont know the answer!
So, when the unit is unplugged, it's dark all the time?

Iím sure that itís undimmed when unplugged so would just be a normal mirror.


Sent from my iPhone using Tapatalk
wullie480 is offline   Reply With Quote
Old 27th July 2020, 10:11   #7
Odd Job
My Gremlin got wet!
 
Odd Job's Avatar
 
MG ZT 2.0 cdti

Join Date: Aug 2019
Location: Derby
Posts: 695
Thanks: 227
Thanked 157 Times in 116 Posts
Default

Ah,
What I'm after is for it to dim more often, so unplugging it would't solve my issue.
I think it's probably down to me wearing specs, and I'm more susceptible to being dazzled.

I think the best thing I can do is see if I can convert it to a manual one, put the human back in charge of the machine!

If anyone know's if this is possible without messing with the wiper sensor, and know's what I'll need to do the job ( obviously a manual rear view mirror for a start, but if I need any different fixtures and fittings etc, ) please post and let me know.

Better still, if someone is breaking a 75 with a manual rear view mirror, please let me know!

Kind regards

Richard
__________________
Ö.And the latest thing to break is.....

The thermostat
The brake light switch ( brake light witch I call it! )
Central locking mind of it's own.
No air-con ( I know what the problem is though )
The Maf
Number plate light circuit board
O/S/F top suspension mounting
The Clutch master cylinder push rod - just snapped
The Radio / CD player - just died.
The internal boot release switch ( witch ) mind of its own.
Throttle Potentiometer - just failed
### MG STANDS FOR "MY GREMLIN" !!!
Odd Job is offline   Reply With Quote
Old 27th July 2020, 10:13   #8
steve-45
This is my second home
 
steve-45's Avatar
 
Rover 75 Saloon CDTi

Join Date: Oct 2015
Location: Belvedere, Kent.
Posts: 3,621
Thanks: 92
Thanked 875 Times in 650 Posts
Default

Interesting thread, Iíve still to fit my dimming mirror but wondered if the fitting thatís bonded to the screen is the same for both mirror types?
steve-45 is offline   Reply With Quote
Old 27th July 2020, 10:19   #9
Odd Job
My Gremlin got wet!
 
Odd Job's Avatar
 
MG ZT 2.0 cdti

Join Date: Aug 2019
Location: Derby
Posts: 695
Thanks: 227
Thanked 157 Times in 116 Posts
Default

I've had a quick look on fleabay, the non dimming mirror looks much smaller in both actual size and the part that goes to the screen.

I'm guessing that the way they fix is totally different.
It might not be a quick and easy swap over, it may be a bit more involved than I hoped.
I dont really want to destroy the self dim, as I want the option to change back if I have a change of heart, or when I sell my vehicle the new owner can put it back to how it was.
__________________
Ö.And the latest thing to break is.....

The thermostat
The brake light switch ( brake light witch I call it! )
Central locking mind of it's own.
No air-con ( I know what the problem is though )
The Maf
Number plate light circuit board
O/S/F top suspension mounting
The Clutch master cylinder push rod - just snapped
The Radio / CD player - just died.
The internal boot release switch ( witch ) mind of its own.
Throttle Potentiometer - just failed
### MG STANDS FOR "MY GREMLIN" !!!
Odd Job is offline   Reply With Quote
Old 27th July 2020, 10:22   #10
wullie480
This is my second home
 
Insignia VX-Line & Insignia tourer

Join Date: Dec 2010
Location: Bunnyville
Posts: 5,084
Thanks: 517
Thanked 981 Times in 754 Posts
Default

I see what you want to do now.
I wonder if the brighter lights are reflecting from the screen and confusing the sensor at the front of the mirror making it think itís light and therefore not dimming the mirror.
I wonder if a filter over the front could help or maybe try tape so itís dimmed all the time?
I believe they are the same fixing in the screen.


Sent from my iPhone using Tapatalk
wullie480 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 +1. The time now is 18:23.


Powered by vBulletin® Version 3.8.6
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.
Copyright © 2006-2020, The Rover 75 & MG ZT Owners Club Ltd