Help identify relay causing battery drain

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Hi all, my 1995 440 1.9TD kept getting a flat battery. Checked the relays under the bonnet, one was constantly powered (getting warm). I need to identify it so I can diagnose the underlying problem.

Looking at the engine bay from the front of the car it's the top right relay, just left of the far right one in the 'point' of the tray.
http://www.wistonia.co.uk/relay_layout.jpg
Removing the relay disables the wipers, rear window heater and front electric windows, regardless of ignition switch position. According to a local garage it should only operate the wipers.

Does anyone know what might be happening? My best guess is the ignition switch has a short, but garage say it's unlikely.
Any help much appreciated.

[GTMaster]

I know that the brake light switch can cause a similar problem. Have any of the fuses gone out?

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No fuses gone the last time I checked.

You're worrying me with the brake switch though, I don't know whether I'll cope if any more of the car's electrics join the party.

[GTMaster]

Not too much of a problem to check, though if the brake light switch does short circuit, then the fuse does go.
Are you sure the battery's alright? Diesel engines do need more power to start....

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Definitely not the battery, recently replaced with a brand new one, and the old one was still just meeting specification.
Measured 150mA current with everything switched off. Unplugging the warm relay, current draw dropped to practically zero.

Will check the brake switch fuse, I don't have any manuals, do you know which it is?

[Paul240480]

As that relay appears to relate to rear screen electrics etc. Have a look at the tailgate wiring loom. Just where it comes out of the roof lining & goes to the window itself. Very often through the boot movement the wires insulation breaks up causing wires to short on the body.

Not sure if this can cause battery drain, but worth checking methinks.

Godd Luck.

[PAW1212]

The items you are referring to should be disconnected by the ignition switch when the ignition is off. The relays can get pretty hot in normal use anyway.
The relay is usually marked with its internal arrangement and the connections to them. You should be able to check if the relay is in the off position with a voltmeter. You can check its operation by placing your finger on it, when it is switched you can feel the click of the relay working.

Otherwise:-
A current drain of 150mA would give perhaps a 1.8 to 2W load, so this could be a small bulb.
Do you have an alarm or immobiliser fitted? That is one of the few items that is still live with the ignition off, apart from the vehicle lights and interior lamps. Check the glovebox one.

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Probably not a short in the wiring loom as everything functions correctly, I will check though.

I've tested the relay which operates fine without sticking, with the ignition switch off it's getting voltage, measured it at the socket, it's warm after the car has been left overnight so definitely drawing current when it shouldn't be.

I really need to identify what this relay is. According to local garage schematic it's either windscreen wipers, or aircon., I don't have aircon. but the relay affects the other circuits mentioned anyway.

Looking at the wiring diagram it makes more sense that this is one of the ignition relays. So if anyone can say with certainty that would be extremely helpful before I pull apart the back of the ignition switch.

[GTMaster]

Well it could be that the relay itself is dodgy, or the wiper switch. Switches can short circuit too...
If it would be an ignition relay, then after you switch off the ignition you'd still be able to measure voltage in the ignition system ( i reckon).
Don't you have a key(label) that explains which fuse is which on the fuse compartment 'lid'?

[GTMaster]

Out of curiosity i checked my relay box, and the relay you've cirlced isn't in it! I guess mine's an earlier model that's why...