Been considering this for a while, especially when the car gets so hot, and got to load the whole family in the car. I'm always last in, with the key, so by then they have baked for a bit.
I think it would be handy in other ways too.

I remember older BMW's used to have a live to the windows, if a front door was open. So maybe for safety I could take the feed from the interior light.

Anyway, I'm just going to find the main feed to the windows, and connect a live to them.
Would I expect any issues with that?

 

I wouldn't do it with a feed from the door switches, the power needed to lower/raise a window or two could well fry the door switches and/or blow their fuse.

Why not take a feed direct from the battery, via an inline fuse, to a relay, terminal 30, (or use a fused relay), and from there to the windows?
Then take a feed from the front door switch to the relay terminal 85, and one from relay terminal 86 to an earth?

That way you have a live to the window switches, fused for safety, and controlled by having, say, the driver's door open. The windows would use the normal supply at other times. Fuse value for the feed would need to be whatever the one is for the windows at present, probably 20A

Just be careful that fitting such a live doesn't intefere with the normal operation of the windows, or feedback into anything else Try it and see, remove it if it does.

 

Thanks, I had a feeling it would be you that replied.

All I need to find out now is where the main feed for the windows are.
Or did you mean not to do that when you referred to the door switches? Or did you mean the actual open switch?

 

Can't you get full closure alarms which open the windows aswell as close them??
Toad/clifford fobs have 1 or 2 buttons to add extras on..

 

On my post above, I'd take a lead from battery, as advised to relay 30.

The others are from the door open switch to relay 85, relay 86 to earth and relay 87 to the present window feed.

You are going to need either a multimeter or a circuit tester to find lives. I have both, but rarely get the multimeter out.

First probe the wiring around the door switch, find a wire which is ONLY live when the door is OPEN.

Then, probe the wires going TO the window switch, find the one which is live when ignition is on.


Those two are your two lives you need to link to, first one to 85, second one to 87.

My circuit tester was around £3 from a carshop.

 

Yes, I was going to add in the original post, that I don't' want a new alarm.
Would rather keep the sigma.