Disco Dome Light Flakiness

[FelixLockhart]

I recently purchased a '95 Discovery, and I've been doing some work on it (mostly electrical and interior), and things have been going great so far. However, last night when I was working on it, the dome lights started acting weird. Normally, I open the door and they come on after a slight delay, and when the door is closed they slowly fade out. Now, when I open any door, the dome lights flash about 5-6 times, then cut off. Also, the door chime when the key is in chimes at seemingly random intervals instead of a steady rhythm.

Any idea what could be causing this, and how to fix it? I checked every fuse and wire I touched that night, and nothing is crossed or damaged.

Another bit of odd behaviour, I accidently turned on the rear defroster earlier this evening when playing with the rear foglights (which is a really nifty feature, btw), and the dome lights acted like I had opened the door. I haven't been able to replicate this, though, so I figured it was just a fluke?

[sidawson]

I've just had all this on my 94. The Dome light is controled buy the MFU (Multi functional Unit) Black box Plugged in the back of the fuse box in the truck not under the hood.
the MFU also has a part in controling the

Heated rear screen
Dome lights
Side and head lights
rear fogs
Headlight power washers
Front wipers
Rear wipers and washer

My problem was simple the fuse I think Number 12 for the MFU was blown Pull yours and check it very closely or just put a known good 10 amp in.
Next to that the thing could be shot there is a test you can do. Try this Diagnostic. If you cant get it to do this I'm guessing only that your MFU is fried and thats only my guess. A new one is $100 plus

1. Close all doors and the tailgate.

NOTE: If the oil pressure switch goes open circuit (engine is started) during the following procedure, the MFU will exit the diagnostic mode immediately.

2. Press and hold the heated rear screen switch and switch on the ignition.

3. Release the heated rear screen switch within 2 seconds and the MFU will beep to indicate that it’s in diagnostic mode 1.

4. Press the heated rear screen switch; the MFU will beep twice. In turn, operate each of the
following switches, rear fog guard lamps, side lights, headlights, front wiper, and rear wiper. The MFU will beep twice each time a switch is operated.

5. Pressing the heated rear screen again will cause the MFU to enter diagnostic mode 2.

6. The MFU will provide outputs to the following in order given below:

_ Heated rear screen relay energised for 2 seconds
_ Courtesy lights energised for 2 seconds
_ Dim dip relay energised for 2 seconds
_ Rear fog guard lamp energised for 2 seconds
_ Headlamp power wash energised for half a second
_ Front wiper energised for half a second
_ Rear wipe/wash energised for half a second

7. The MFU will then exit the diagnostic mode.


Good luck

[FelixLockhart]

Wow! Out of all the forums I've posted to, that's the most useful-sounding reply I've gotten so far

I'll give it a shot after work today, I'm hoping it's a fuse problem and not a bad MFU. Thanks!

[FelixLockhart]

Just got finished with everything, and the lights are working. Not sure why they are, but they are. I checked the fuses, they were both fine, and I removed and reinstalled the MFU itself, then ran it through the diagnostic sequence a couple times, and after the second trip through the diagnostic, it worked. Thanks again!

Now I just need to get that diff lock lever unstuck so I can go off-roading

[Carlos]

Call that a Land Rover "re-booting" ,just like your pc.
Sometimes this fixes electrical problems on Land Rovers.
Carlos

[FelixLockhart]

Bleh, now it isn't working again. I'm going to play with it some more, but I may have to take it to the dealership, which is about three hours away, and their service department isn't open on Saturdays, which are my only real opportunities to get anything done

EDIT: It works now, silly Lucas electrical systems [rolls eyes].

[Adam in NYC USA]

Did you get those Lucas bugs squashed yet?

Adam

[FelixLockhart]

Actually, it finally worked out. The dumba** previous owner had one of those connectors that piggybacked on a fuse for his hands-free cellphone kit, which I removed shortly before this happened. The connector forced one side of the fuse holder wide enough that it wasn't getting good connectivity. Since I don't want to buy a whole new fuse box, I just stuck the connector back in and wrapped the exposed end with electrical tape, and life is good again