OK, what if it isn't the switch? My LR wouldn't accept being put into Drive without lowering itself. I replaced the switch, and now all the warnings are on the dash, and the LR doesn't stay upright; it drops to the stops.
Hard reset had no affect.

What to try or do next?

 

It appears that the good news is that installing a new brake light switch has made a difference. A apparent negative difference but that suggest something was wrong with the previous switch.

Defective rear signal light bulbs can really confuse the computers and create lots of error messages, usually cruise control not available, air suspension up down frozen, and the really scary one, tranny broken, replace with new - that sort of thing.

Rather than pulling the signal light bulbs, an alternative is just to unplug the tail light assembly completely and see if that makes a difference.

If not then per the link below, remove the F26E fuse in the engine compartment if the 3 is up to at least normal height. I presume that the 3 will rise, it is just that when it is put into drive, it drops. As such, pull the F26E fuse prior to putting in drive. You should now be able to drive near normally as the air system should stay up. This now gives you the time to figure out where the problem really is.

DISCO3.CO.UK Photo Gallery - LR3 Air Suspension fuse 35P ECU Manual Shut Off Switch

 

Agreed! Thank you. I changed my brake light switch and replaced all the bulbs with the RIGHT bulbs and my transmission, engine, hdc, special programs faults all cleared. I would not have known what to do if it was not for this forum.

 

Just took both rear housing out based on above and when I unpluged the tail light assembly completely out one of them was wet dried it out tested it with housings unpluged and all issue were gone asembled back togheter and all errors are gone (Tranmision traction lowered, abs, brake, suspension dash lights all turned off) Hope it last any recomendation on keeping water out of light housing or should I just use good old electrical greese?

 

I assume it is rain water that is getting in. The plastic must be cracked somewhere. I would sort of float the tail light assembly in something like a bath tub and see if you can determine where the water is getting in.

If successful, then use plastic glue to plug off the cracks - just might work. I assume that somewhere there is a drain hole designed in to the assembly so make certain you are not plugging that hole.

And yes, use electrical grease on the bulb bases before you insert them in their sockets - reduces corrosion due to moisture.

 

Ok, at first it was just annoying... Now it's down right frustrating! We have what I thought was this problem... Driving down the road and the doors lock and unlock, four ways start flashing, radio/nav/and hvac all turn off. Suspension doesn't drop but the system is unresponsive and says "shutting down"... The truck still drives and sometimes, it randomly goes back to norm, but keeps doing this! Often times then it won't start, especially if it was in one of these episodes when shutting it off. I've replaced the battery, brake light switch and ALL the light bulbs are LR (a small fortune in bulbs).... I've taken apart the tcm and interior looking for corroded wires or such and nothing... Any other ideas???
It is a 05 with 46k on it.

 

Update: After a few weeks of fighting with the cluster floating in the car (unbolted and dash surround apart), so when an "episode" happened i could move it around to make it normal again... i finally did some further disgnostics... ie. poking and proding... it appears the connector was very loose (probably throwing off some of the pins), so i wedged some cut off zip ties in there as shims and it appears to work fine now! 2 weeks of driving around ok. i guess that was the problem! just a loose connection! hopefully.

 

Glad everything worked out. Where is the "connector"? Thanks! Still have issues here, still won't start.

 

Behind the instrument cluster... Have to take a bit off surrounding, but I was able to get it out without taking off the steering shell ( as the repair manual suggests).

 

Brake switch was simple and worked on my 06 3. Thanks !!