Discovery 2 SLABS issues

I've currently got a variety of, apparently, unrelated electrical issues that are proving a bit hard to track down - but not, as far as I know with the air suspension.........

As I recently had some sagging problems, I've just changed the suspension air bags - and decided to install an indicator to let me know when the compressor was running, so I could see if it started running more than it should. Ebay supplied a pre-wired 12V LED that flashes blue/red which I wired between the SLABS output (C0655/6 Brown/Purple) and earth. I mounted the LED on the blank switch I have below the hazard warning light switch.

Very nicely flashed blue/red when the compressor runs. BUT, at pretty much all other times, there's a low level blue flicker - it might stop for a couple of seconds after turning on the ignition etc But it was still flickering this morning, after the car had been sitting overnight.

• Any ideas as to why there's a low level output from SLABS (I presume) all the time?
• Is it correct? Or a symptom of a problem somewhere?
• I'd quite like to get rid of it - wondered about sticking a capacitor in parallel to soak up the "noise" Any thoughts?

Any comments & ideas gratefully received!

Might be monitoring the line, or have you got a different year wiring diagram to the 2000 MY?

There are 4/5 different years in the RAVE circuits.

What you have done looks fine for the 2000MY.

Does the LED have an internal resistor, what value? and is it a dual colour with two leads or three?

Peter

Did you observe that flickering after night from outside without unlocking or you opened the door and saw it?, unlocking or opening a door will wake up the SLABS and some small voltage on outputs could occur even without request cos it works with transistor switch circuits and that LED bistable circuit might sense it

Hi

Thanks for the comments.

It's a 2 lead LED with a suitable (value unknown) resistor for 12V - it does its switching between the 2 colours internally. I'm pretty sure that it's flickering before I open the door, but I'll make a point of checking next time. As the output I've attached it to directly feeds the compressor relay, I'd expected it to be a solid on/off as I don't see any need for communication. And I'd have thought the route to earth via the compressor relay coil would have held noise down.

Maybe I've just underestimated the amount of electrical noise floating around?

Anyone see any dangers of sticking a capacitor across to ground? To try to take out the noise?

I've currently got several apparently unconnected faults - think some caused by me stupidly shorting pins on the D connector on my Nanocom....... Wonder if this is another? I thought some might be a result of water getting onto the back of the fusebox (had issues before) - but a changed fusebox shows the same problems...

Andy

I wouldn't put anything like a capacitor across those terminals without knowing what is driving them inside.

Peter

An LED like digital multiple meter make it easy to find spurious voltages in vehicle, that's why those of us who know use an anolog meter for testing vehicle wiring or even a bulb and a piece of wire.
Try your led directly on the feed to the compress as that supply will be sourced from the vehicles battery and not via an ecu as I understand from you comment the relay is.