Disco 1 Strange issue regarding fuse

Hi all I'm in need of some advice little while ago my interior lights would not work turned out to be a door trigger now just recently the fuse f6 blew tried replacing and it blew stright away looked for all obvious issues none found so replaced it while lights and stereo was off so there was no load ended up useing a 15amp as all I had at time that worked for a little while but while hoovering the car it popped again spoke to a garage recommended useing a 20amp bit sceptical as it's twice the rated power so replaced it all seemed fine for nearly 3 weeks until today I could smell burning from around the fuse area pulled the fuse it's fine and issue as gone but now no radio lights e.t.c. only extra item fitted is my cb but only the earth goes to the same body earth as interior light main power comes from cigarette lighter what could I be missing cheers all

F6 from which fusebox, F6 interior fusebox is rated 20A in the diagram and goes to the cigar lighter and seat heaters F6 sattelite fusebox goes to interior lamps but it's rated also 20A and goes to the caravan socket too(12S) so if you have that kind of socket fitted better see if there's not a short there cos that's common

Thanks for the reply had a nosey at lunch think I could have messed up when fitting cb does the black wire attached to metal plate route to mfu as mine now as a hole in its side cut cb out replaced fuse f6 sat 2 with a 10 amp in case issue not fixed fingers crossed it is just orderd correct mfu

F6 would blow only if one of those circuits connected to it has a short to earth...it has nothing to do with the MFU which is linked to F15 fascia fuseboc... though why would you put a 10A fuse wherev a 20A is required?

OK quick update mfu removed found large component in top corner burned out after research found its the part that controls interior light on and timer so I either have a faulty mfu or there an issue with wireing removed all interior bulbs only running a 10amp to play safe plus was what it had fitted so was not aware until your second post should be 20amp will change when changing mfu

Sparky1985 said:

OK quick update mfu removed found large component in top corner burned out after research found its the part that controls interior light on and timer so I either have a faulty mfu or there an issue with wireing removed all interior bulbs only running a 10amp to play safe plus was what it had fitted so was not aware until your second post should be 20amp will change when changing mfu

Click to expand...

pic of component?

I forgot to take pic of component as needed to get running to get it home as was currently at work at time this is what made me dig

Found this pic online it's the component in top left with 3 legs and above black plug

If the MFU suffered and F6 blew the problem is somewhere on that circuit after F6 as in the diagram i posted which was overloaded ...what consumption has that CB you wired to the cigar lighter though?

Sparky1985 said:

Found this pic online it's the component in top left with 3 legs and above black plug
View attachment 107001

Click to expand...

can yu get a better pic of the component and the writing on it? it looks like a regulator - easy to replace

Yeah I'm pretty sure it's to do with interior lights circuit which is on the f6 fuse because of the damage to the mfu the component has over heated what I now need to investigate is why has it
It could be I screwed up when fitting CB wireing ground to the light ground ?
Or there could be wire damage on the circuit somewhere ?
Or don't think likely but could be the led bulbs I fitted ?
As for CB consumption I'm not sure it's a basic midlands unit
And as for component I found my info on another forum here
http://landroverforums.com/forum/discovery-i-39/mfu-internal-problem-40965/
Sorry if links not allowed

ere yar....

Suspect failure - top left transistor, which is a P55N06. Plastic melted on case adjacent to transistor from long term heat. This device is the only high power device on the board, and is probably used to switch on the interior lights and slowly dim them when turning off.

The transistor has no heat sink. IMHO this will lead to failure over a long period of use. A small soldering iron can be used to swap this one out ($8 on line). If I were to do this, I would add a small heat sink.

For the rest of us, perhaps we should consider using fewer bulbs on the interior lights, or lower amp drain ones. Some of the new LED replacements offer a lot lower drain (like 30 or 40 milliamps vs 830 for a 5008LL cargo light bulb). The cost of an MFU, and the "fun" of remove/replace the fuse panel, might make the bulb change worthwhile.

Not sure if the guy is correct but it's that component that's burnt on mine

if it is the little black 3 legged component your needing i have an old MFU here that had many problems but that part is still good i'll be happy enough do take it off and pop it in the post for you if it helps, drop me a message if you need it. kept it for taking bits off for repairs. so far its had a leg removed to fix the current MFU im using lol