Passenger Fusebox problems.

[Ian Morrison]

Hi, I’ve been getting problems all that seem to originate from the Passenger Fusebox or the generic control unit. The first thing that stopped working was the cornering light, Then the Headlight washers, Then the Sun Roof and today the upper Tailgate release motor stopped working. I’ve been told that I will most likely need to buy a new passenger fuseboard which means my keys will have to be reprogrammed to the new fuseboard. Has anyone encountered a fuseboard with similar problems and any idea how much a new fuseboard and reprogramming costs. I know this will have to be taken to a Land Rover dealer to get this done. If anyone has had similar problems let me know as I’ve been told by a Land Rover mechanic that I should be careful driving the car as every electric part is controlled by this Fusebox and parts will fail on a regular basis until eventually the engine will cut out as this too is controlled by the generic control unit. I was also told that this problem is very common on the Land Rover Discovery 3

 

[Rubber Cow]

Have you checked the wires under the passenger side foot well....under the carpeting?
This is a common place for shorts to happen and for water leakage to compound the problem.

 

[ambrown31]

I would make sure someone finds the actual issue before swapping out parts. It could be a short somewhere that would still be there after the dealer spends thousands of dollars replacing all those components.

 

[bbyer]

First of all, per the second post, I doubt that you have a "fusebox" problem. The solution is not that drastic or expensive, but it is much harder.

When someone says you have a fusebox problem, what I think they are suggesting is that there is a problem with the printed circuit board attached to the back of the fuse box.

The pcb is what I call the car computer and yes, does pretty much control whatever goes on in the vehicle. This is where the VIN is imprinted into the brains of the 3 and hence yes, if you get a new "fusebox", then lots of reprogramming has to be done, or more correctly, I think how it really works, is that to order one, you provide LR with your VIN and it comes programmed with the factory software load - hence keys etc will still work, but you will be broke and not beable to afford fuel for your 3.

Also there is a backup chip located on the rear of the instrument cluster that backs up the info saved on the primary pcb. I say this as the single large electrical connector that plugs into the rear of the instrument cluster over time comes loose and has to be replugged back in. The clue that this is loose is lots of trouble lights start to show up on instrument cluster or gauges such the the fuel or temperature stop working. Most often the engine still starts and runs etc but lots of nasty messages display or nothing displays. Sometimes the engine will start and then quit or the tranny will not shift.

As the second post suggests, I would first start digging into the wiring bundles located under both front door sill channels. Over time, water seems to collect in there and start corroding the wires within. There are some really thin 22 gauge wires in there that go first. These relate to the door locks and lights in the door buttons.

This link has pictures of the door sill wiring and links to other threads.
I would explore this first as for the most part, I find that the actual printed circuits boards do not normally fail, but the wiring and connectors to them sure does - if that makes you feel any better.

https://www.disco3.co.uk/forum/topic54235.html?highlight=+remote++locking