MGTF rear mirror wiring

MGTF rear mirror wiring

Author
Discussion

subseamatt

Original Poster:

80 posts

81 months

Sunday 29th September 2019
quotequote all
I'm trying to finish the upgrade to an MGTF rear view mirror in the Tamora (with the integrated map lights). All done now, including connections to permanent live & ground, apart from final connection into the door-switched wire for the courtesy light function.
From the Tamora wiring diagrams, I thought it was the Purple/red wire in the loom next to the driver's door hinges where i was going to tap into, but this doesn't seem to switch positive with the original hoop interior light.
Does anyone who's done this mod already know which wire drives the courtesy lights (or what I may be misunderstanding)?
Thanks. Matt

Penelope Stopit

11,209 posts

123 months

Sunday 29th September 2019
quotequote all
White/Purple @ RH&LH door pin switches are switched to negative on opening of either door

diagrams are often incorrect, if you can't find the White/Purple look for Purple/White

Good luck in finding

subseamatt

Original Poster:

80 posts

81 months

Sunday 29th September 2019
quotequote all
Ahh great. Thanks. I've found a purple white so I'll stick a voltmeter on that and see what I get. Haven't found where the door pin switches are hence my trouble. I take it they are in the catch mechanism somewhere?

Penelope Stopit

11,209 posts

123 months

Sunday 29th September 2019
quotequote all
Pretty sure the door micro-switches are in the door catches, it looks like they connect to the door ECUs and to the relay unit (RAS) fitted in the area of the tunnel

The thing to be aware of is will the micro-switches reliably carry the interior lights current (I doubt it)

Struggling to find the complete circuit at present and running out of time

phillpot

17,354 posts

197 months

Sunday 29th September 2019
quotequote all
Penelope Stopit said:
The thing to be aware of is will the micro-switches reliably carry the interior lights current
Fit LED lamps, it'll be fine

Penelope Stopit said:
Struggling to find the complete circuit at present and running out of time
Are you dying?

subseamatt

Original Poster:

80 posts

81 months

Sunday 29th September 2019
quotequote all
Perfect. Thanks both.
I've got LED bulbs in them. If it goes to ground when the doors open then I'll probably need to stick a relay in to invert that signal anyway, so all should be fine either way.
Hopefully I'll get some time one evening this week to continue.

Penelope Stopit

11,209 posts

123 months

Sunday 29th September 2019
quotequote all
subseamatt said:
Perfect. Thanks both.
I've got LED bulbs in them. If it goes to ground when the doors open then I'll probably need to stick a relay in to invert that signal anyway, so all should be fine either way.
Hopefully I'll get some time one evening this week to continue.
Ok then y

Yes good idea to fit a relay for polarity switching

Here is something else for you to think about

With the door switch switching negative to the added relay coil terminal 85, there will need to be a positive @ added relay coil terminal 86

This is a but.........................but worth considering

When the door is closed there will now be a positive voltage starting at terminal 86, travelling through the relay coil to terminal 85 and onwards to the door ECU and RAS

There is a possibility that the above will affect the operation of the door ECU, RAS and alarm to name a few off the top of my head

Best fit a diode in series with the switched negative from door switch to added relay or use a relay that has a built in diode in series with its coil to prevent the above from happening

You've very likely already thought through this

In case you haven't