Hi guys,

Been dealing with a battery drain problem since getting my L322. I have replaced the FSR for a brand new one but the problem still persists.

I have used a clamp meter around the negative lead to the battery and have figured out that fuse 12 is the culprit. With F12 in place the current draw when locked (and P light off) is ~3 amps, when removing the F12 fuse the current draw drops to around 0.5amps. So better but not perfect.

What exactly could the fuse12 current draw point to? Air con? Heated Seats? etc???

Thanks in advance

Well, that is what the handbook says fuse 12 is for.

Possibly easier to rule out heated seats first by unplugging them and see what happens?

Could also be the pcb behind all the switches and knobs in the centre console? .
Experience is the only genuine knowledge, but as time passes, I have forgotten more than I can remember
Volvo V70 P2 2006 2.4 Petrol 170bhp Estate SE
MG Midget Mk1 1962

Previous: L322 Range Rover TDV8 3.6 2008; L322 Range Rover TD6 3.0 2002; P38A Range Rover V8 1999

Do you have a rear fan blower? If so there is also the equivalent of the front fsr controlling it. Does your rear fan speed rise and lower in speed if you turn the control knob. If not I would be inclined to think about the fear fan fsr.
My rear fan is a bit erratic when I turn the control knob leading me to believe its fsr is faulty but it doesn't have any current drain through it. It might be worth unplugging the rear fsr to see if that cures the current drain.
Fuse 12 serves the hevac ecu which has numerous sensors connected to it as weel as the blower fans, flap motors etc any one of which could have gone down.
The easiest way to find your drain fault might be to get you car onto diagnostics to see if anything is highlighted.

So I tried to trace the fault but fuse 12 is connected to sooooo much kit I really don't know where to start. The rear blower power adjuster is a bit temperamental as it feels it's either full on, or off.... maybe that is the FSR that needs looking at?

Any idea where the rear FSR (Final Stage Resistor) is hidden?

As a temporary measure I've added in a relay controlling fuse12 by using fuse7 as the trigger, you might ask why? Well i;ve bought a new battery and don't want to ruin this one!

great idea to relay fuse 12 temp measure to keep the fatty working as it should without to much work (until you get the time to do the work)

The rear fan fsr is mounted next to the fan itself under the centre console.

I've got a battery drain and fuse 12 is at least partly responsible. Did you solve your problem with fuse 12? All the best
Chris

On my prev RR, an 03 TD6, the battery drain was caused by one of the front headlight washers. I'd have to look back through my comments on here but fuse 12 rings a bell. 2004 Vogue SE TD6
(Also a LR 90 V8 & RRS, just because)