Hi guys!

I was wondering if you could help me with this.

My discovery's back and trunk light stays on all the time and are discharging my battery.

Also there is a high pitch ring that sounds as soon as I put the car in D now and won't stop till I turn it off

What could it be?

 

There is a small plastic box on back of the fuse panel under the dash. It is the Multi-function unit, controls dimming (or not) of interior lights, other things, and has a sounder that alerts for various things. Suspect you may have a bad one. The RAVE has a test method:

Diagnostic Procedure
1. Close all doors and the tailgate.
NOTE: If the oil pressure switch goes open circuit
(engine is started) during the following procedure,
the MFU will exit the diagnostic mode immediately.
2. Press and hold the heated rear screen switch
and switch on the ignition.
3. Release the heated rear screen switch within 2
seconds and the MFU will beep to indicate that it’s in
diagnostic mode 1.
4. Press the heated rear screen switch; the MFU
will beep twice. In turn, operate each of the following
switches, heated front screen, rear fog guard lamps,
side lights, headlights, front wiper and rear wiper.
The MFU will beep twice each time a switch is operated.
5. Pressing the heated rear screen again will cause
the MFU to enter diagnostic mode 2.
6. The MFU will provide outputs to the following in
order given below:

Heated rear screen relay energised for 2 seconds

Heated front screen energised for 2 seconds

Courtesy lights energised for 2 seconds

Dim dip relay energised for 2 seconds

Rear fog guard lamp energised for 2 seconds

Headlamp power wash energised for half a second

Front wiper energised for half a second

Rear wipe/wash energised for half a second
7. The MFU will then exit the diagnostic mode.

You may also be having a tone warning from a faulty switch indicating CDL position.