Ok, at first it was just annoying... Now it's down right frustrating! We have issues... 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! I'm thinking it is going into "crash mode". 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

 

check the connectors under the driver side foot panel. probably got water from the roof drain hose getting into the car and corroding the connectors. especially the green connector .

 

well after a few nights of further ripping apart the interior... i narrowed the faulty location to be the instrument cluster area... took the cluster out, all the soder joints look good, no burn marks, took apart the electrical connector and all the pins are ok... put it back together and we'll see...

 

you have a wire rubbing on a stud grounding the can lines. try excessive turning or stopping to see if you can get it to happen. trust me this isn't something codes will tell you. the network is shutting down. look under your seats for worn wires as well.

 

Well it was wishful thinking .... I thought it was the instument cluster but today it was still happening, and tapping the cluster didn't seem to do anything, back to the drawing board

 

...did you check the wiring under the passenger side floor? I saw driver side above, but not passenger...

 

ok... maybe a very basic/stupid question... i can tear down the footwells to expose all the wiring and see it goes under the door sills... i have the "scuff plates" off both sides and see the plastic housing that the harness runs in... how would i go about getting into that housing or removing it? do i have to complete remove the seats to pull the carpet back enough... anyone do this?

 

UPDATE!!!
I pulled the cluster out again and scowered it with magnifying glass again to look for burn/bad sodder... nothing... so i pulled the connector apart again and messed with wiring... nothing looked bad, we HAD to use the truck yesterday on a trip to baltimore, so i put it back in without screwing down the cluster, just left it "float" there (asking the wife to be very careful not to bump it as it was in working mode without errors). the truck ran smoothly all the way down and back! hopefully i can put the cluster in officially and the problem was just a loose connection and not the board itself!

 

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.

 

Hey guys, this is my first post but I wanted to thank Bmwrovers for helping me identify my issue on my 2005 LR3. I was having the same issue where the car would randomly not start (Temp gauge goes to dashes, climate goes out, radio says shutting down and hazards would turn on), I could bang on the dash board and it would start and everything would return to normal. Today I finally took the dash apart and started to wiggle the harness on the back of the cluster, I found it would make the issue return. I know the can bus wires communicate with the dash, and can cause these weird issues. So I pulled the cluster completely out and checked all the solder joints, I found where the plug attaches to the circuit board had just a small amount of solder on each terminal. I pulled the solder iron out and re-heated the terminals (adding a small amount of new solder) and put it back together. After reconnecting the dash, no issues everything is back to normal even after I wiggle the plug. This issue can be frustrating to diagnosis and BMWrovers got me started on the right path, I hope this helps for people having this issue.