Yep, you have to reprogram one of the computers to think that no SLS system was purchased with that vehicle. The drain problem is when truck is off, and periodically the computer decides it is time to level the vehicle. So it cycles the solenoid valves, and if a compressor was still live it might even run it.

Come to think about it, Rover might be testing for those components hooked up by running a very small current out there, to "see" the coil of the valve. You might try taking that ground apart, and introducing a resistor (like 1000 ohms or 470 ohms) in series with the SLS ground. Then it can't put full power to the devices, and the resistor would limit current to 12 or 25 milliamps to ground. Maybe the SLABS can be "fooled".

 

If you want to stop the drain caused by an SLS unit, go to a shop and have it shut down thru the ECU and make sure to pull the relay.

 

Or ... if I was considering upgrading to the '03-'04 SLABS ECU anyway for the improved TC programming, etc. I could try to ensure it was from a non-SLS truck, right? That assumes it's programming in the SLABS ECU that's relevant, and not in the BCU.

 

Okay, next steps. When I monitored the parasitic drain earlier this week the biggest amperage drop came when I pulled fuse F26, which (I think) powers the AUX circuits off the ignition switch (the meter dropped from 95 to 38). Does that mean the ignition switch might be defective, allowing current to leak past it to a downstream accessory even when the switch is off? If so it's not anything obvious; the things you expect will shut down when the key is removed do so. If not it seems like there'd be a long list of components running off the AUX circuit. I tried to use the DII electrical circuit diagrams to trace what specific items I should check but I quickly got confused. Any ideas? Thanks.

 

Replacing the Slabbs won't benefit or fix this problem. Need to shut of the SLS the the ECU.

 

There is a ground from the driver's side cylinder head (USA) to the firewall.
Probably will not help SLABS.

I would put a little 12 volt bulb on the battery - in series with the ground and then
have the bulb where you can see it.
Then debug it all by pulling out fuses.
Or connectors on devices.

 

Fuse 26 powers the AUX circuit relay coil, might try unplugging it. The relay switches power from fuse link 7 under the hood to a variety of things. Perhaps relay fried?

 

And now the power drain disappeared over the weekend just as suddenly and mysteriously as it appeared a couple of weeks ago.

I wonder if the AUX relay Savannah Buzz referred to was failing but started working again? If the problem reappears at least I'll have a head start trying to solve it. A-B sells the relay for $20. Maybe I'll look for a less expensive spare at Advance Auto or somewhere or pick up one or two from the next parts truck I encounter.

 

In general, relay contacts are small points that touch to transfer power. Many are made to slightly "wipe" when engaged, to keep the surface of contact points clean. If a current surge makes the points "pitted" they can mechanically "stick". If you tap on it and it releases this is a sign. Like you said, swap with another less critical relay.

 

After a year plus my parasitic drain returned, and this time I have traced it to the SLS, which was disconnected years ago when the coil conversion was done but which was apparently not turned off in the SLABS ECU.

I have an appointment later this week to take the truck to the shop that installed the coils and have them reprogram the SLABS ECU to the coil springs setup.

My concern is that these knuckleheads won't know what to do. I see the programmable options in the BCU section of the RAVE but SLS is not listed. Can one of you who knows specifically what to do please respond with step-by-step instructions that I can share with the tech in case he is befuddled? Thanks.