Factory Alarm help?

[Sooty]

Mate of mine has a 91' Auto 325 Touring that's had a small fire under the bonnet (fuel leak) that's taken out a chunk of the engine loom.

He's managed to get most of the loom back to working order but he's hit a stumbling block with some of the alarm wiring.

It's got a factory 3T-E30 alarm system fitted & he could really do with a wiring diagram to help.

I've checked all the usual places (ETM, Haynes Comic, Bentley, Diakom, etc) but I can find nothing on the factory alarm systems.

Anyone know where to find one?

I know the obvious answer would be to rip it all out & fit an aftermarket job but the guy's on a very tight budget so that's not an option.
He's also a bit of a purist so is keen to keep everything original.

Can anyone help?

[Brianmoooore]

Only alarm wiring under the bonnet is a seperate loom to the sounder unit, which is just a bunch of wires passing through with no branches or connections. and a single wire to the bonnet switch.