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MG MGF Technical - mirror heater switch

I want to be able to switch off mirrors heater on my mgtf.
Normally, it is always on (when engine runs).
I want to switch off when I want.

to switch I'm thinking to use rear screen heater switch (like in many cars), so I have to know how other rover cars system runs. That to create in my mgtf the same system.

Have you got electrical diagrams about mirrors heater installed in other rover cars?
cnerone

I think this has been done in the past (but i can't remember where i saw it!)

The car in question had a small rocker switch set into the top of each door card, under the mirror adjuster handles. It looked very simple to install (i assume just a switch locally for each mirror) and looked very subtle. :-)

Hopefully there are pics on the web somewhere and someone wil come back with an address.

SF
Scarlet Fever

Can we ask why you would like to turn off the heated wing mirrors! Is there an advantage that you can see.
tim woolcott

Yep - Italy is warm enough already without putting out more heat:)

Ted
Ted Newman

I live in italy. The italian summer is quite hot, so adding sun heating and electrical heating mirrors become to hot. It causes crashing to external black or painted material.

cnerone

Does the heating element really give out this much heat to cause the paint and plastic to crack, or would it happen anyway with extreme heat.....
tim woolcott

cnerone

Mirror heater switch link.
http://www.mgfcar.de/mods/carl.htm

Peter

tim woolcott:
I eared it.

Peter:
I dislike this modification. I want to make a less dirt solution.
cnerone

http://www.mgfcar.de/schedules/sb23.jpg

shows light green wires going to the door mirrors, there is nothing else in the doors which requires 'running' voltage, and nothing on the diagram between the '808 header joint' and the mirrors, so if you can find the header joint* and then if you can work out which wires to cut, then you could run a wire from this to the heated rear screen:

http://www.mgfcar.de/schedules/sb20.jpg
Black with green tracer (available at the switch)

Looks to be Fuse 18
http://www.mgfcar.de/schedules/sb3.jpg
Does anyone know what else is on this fuse, I can't see anything else, but it seems a bit odd to have a fuse just for the mirrors?
Will Munns

Will,
I was thinking about adding a relay (connected like 407 relay) that switch mirrors heater.

What do you think about this idea?
cnerone

I think the idea of connecting light green wire to heated rear screen is dangerouse because in the summer (when hard-top is not mounted) mirrors receive the current for heated reaer screen to.

It's right?
cnerone

>It's right?
Nope, you switch the voltage, not the current:
V(oltage)=I(current)* R(esistance)
so when the hardtop is not on the resistace of the circuit is higher, so for the same voltage (~13->15 volts) you will get less current.

>I was thinking about adding a relay that switch mirrors heater.
Probebly a good idea, although you wont cause any damage to the system without a hardtop on, with it on you might overload the system if you connected directly to the hardtop wire, adding a relay is neglegable in current draw.
The wire used to run the rear screen relay is Green with Orange :
http://www.mgfcar.de/schedules/sb20.jpg
but it would probebly be easier to use the Black with green tracer (available at the switch) to power the reley

Will
Will Munns

If I use switch wires I "lost" an important function (auto-off after 15 minutes):

switching on:

hard-top heater on
mirrors heater on
led on

after 15 minutes:
hard-top heater off
mirrors heater on
led off

It will be possible mirrors heater runs and I think it's not running.

cnerone

The switch is momentry, the ECU decides when to hold on the voltage to the relay (look at the dig). The 'led' is actually a bulb and it is connected directly to the same wire which comes from the relay to the rear screen. There is no obvious way to lock the mirrors on using the rear screen heater switch. Unless you wish to lock the new mirror relay on once you have pushed the switch until you turn off the engine. If you wish to do this then the circuit is quite simple...

Relay has 5 contacts, 2 for the input voltage, one marked NC (normally closed when relay is 'off'), one marked NO (normally open, closed when relay is 'on') and common, which is the input to the switch, shall we call these (A,B) for input, (C) for NC, (D) for NO and (E) for Common.

Diode has Two ends, the symbol is an arrow pointing at a bar and points from +ve to negative when the diode is passing current, the bar is the ring on one end of the diode. lets call this (F) for the end without a ring and (G) for the end with a ring.

Cut the light green wire.
Connect the end which goes to the fuse box to common(E), connect the other to NO(D).
Connect the diode (F) to the rear screen wire (Black with Green stripe) and the other end to the relay (A)
Finaly connect the other terminal (B) on the relay to ground (any black wire)

This will give you your mirrors on when screen on, to have the mirrors on from when you power the screen to when you switch the ignition off add a link between the relay (A) and the relay (D).
Will Munns

I want to create a system by which mirrors heater stay on until enigine is turned off OR switch is pressed again.

Have you any suggest to do this?


I need to know where can I buy the relay and where the switch (do you know if there are other rover/MG cars in which are used this parts?), too.
cnerone

I'm thinking to install a new switch to do it.
this system could be fully unconnected from rear heater. So I can use mirrors heater even if I don't use rear heater.

how to create this system?
cnerone

If I connect a new relay to the same wires connected to rear heater? the same excluding common input and normally open/closed output (I have to interrupt mirrors heater power wire)
cnerone

And then, Hella does a nice wireless remote control unit.
12 V Part number 6ZN 157 010-001

http://www.hella.com/produktion/HellaPortal/WebSite/Internet_en/ProductsServices/ForDriversAccessories/Radio_Remote_Control_Unit/Radio_Remote_Control_Unit.jsp

If you get two you can easy switch both mirror heaters independent.
;)

Dieter K.

>I'm thinking to install a new switch to do it.
>this system could be fully unconnected from rear
>heater. So I can use mirrors heater even if I don't use
>rear heater.

>how to create this system?
If you don't have Aircon then buy the recirculating switch, this is a toggle on/off switch where all the others are momentry

>I need to know where can I buy the relay and where the
>switch (do you know if there are other rover/MG cars in
>which are used this parts?), too.
In england I would use Maplin or RS, the diode is any generic rectification diode (not signal diode), and the relay is any 12 volt relay that can switch 10 Amps, if you find one which does not have the NC terminal then thats fine (because we dont use it) but they are unusual.


>I want to create a system by which mirrors heater stay
>on until enigine is turned off OR switch is pressed
>again.

>Have you any suggest to do this?
Now you're getting complex...
Can anybody tell me -

Does the light come on when you press the button or when you release it?
Does the light go off when you press the button or release it?

Will
Will Munns

Have I missed something?

But this seems an awful lot of trouble just to switch off the mirror heaters - which use so very little current and whilst I am sure that a 'tree hugger' somewhere will tell us it adding to the worlds pollution problems I just can not see the point of the expense and trouble.

Ted
Ted Newman

>Have I missed something?
post number 5
Will Munns

Sorry Will but I think that is a load of cobblers - yes the glass gets warm but it aint going to burn the paint work!

Remember that the element is only on when the car ignition is switched on and then you are normally moving and so have a certain amount of cooling and there is ventilation around the glass.

Also I have been down to Italy many many times - in fact I even worked there some years back - and yes it gets warm but not enough to burn the paint work on the MGF.

If the guy (or gal) is having problems then I think it must be something other than the mirror heaters.

And this problem has never been reported by any other 'hot climate' users.

All IMHO of course.

Ted
Ted Newman

Also they have only had the car for 1 or 2 months (not clear from other threads when it was purchsed) so it can only be a fear of damage rather than any experienced damage.

JohnP

I read in newsgroup it.discussioni.auto:
there are some italian tf owners that has mirrors paint leaked. They say that this problem is caused by internal heater that add temp to summer hi temp
cnerone

This thread was discussed between 22/04/2003 and 29/04/2003

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