Dead clocks.....

Somebody help!

My ancient 300tdi Discovery has started blowing the 10A instrument fuse, on number two now so can't ignore it... with the collective mine of information here, somebody has experienced it, and fixed it, before....

Cheers

Mac

Reply to
oldMaxim
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Have you fitted anything new recently? Anything else other than the clocks run off it?

Lee D

Reply to
Lee_D

Or conversely removed anything recently like a radio. I say that as I removed a naff radio I didn't want from my 90 and a couple of years later started to get strange electrical problems, fuses blowing, eventually tracked down to the original bad installation of the radio, but only after changing some switches and lots of investigation work.

Reply to
Bob Hobden

...nothing new fitted or unfitted since a new radio was fitted four years ago - I'm wondering if my alternator could be playing up? I'm no electronics wizard, so really need to see smoke and sparks before it'd be obvious.....

Reply to
oldMaxim

...nothing new fitted or unfitted since a new radio was fitted four years ago - I'm wondering if my alternator could be playing up? I'm no electronics wizard, so really need to see smoke and sparks before it'd be obvious.....

Was it fitted with those horrid blue clip things that cut into the existing wires? It was those that caused all my electrical problems and removing them and repairing the damage to the wires behind the fuse box was not easy.

Reply to
Bob Hobden

Hi

You need a manual with the correct wiring diagram for you version of the Disco (there are many!)

Then, and only then, can you find out what that 10A fuse supplies power to.

If you can't get the correct workshop manual, suprisingly, the Haynes books have a lot of detail in re Disco electrics.

The secret in fixing faults, is to stop and think about what works what, and when. Fault finding is a logical procedure, also only change ONE THING AT A TIME when you do something. Or, you'll lead yourself right up the garden path... If changing something does not make any difference, put it back to original again.

Tip: Temporaraly replace the 10A fuse, with a 21W bulb (old indicator for example.) It should pass enough current for things that work OK, but only light up bright when the fault occurs, you can then poke about and see what you can find.

Take care, low volts can still hurt/kill, but by burning if not shock.

Dont replace with bigger fuses, or you'll end up with a wiring fire, and I can tell you from first hand experience, you dont want one of them!

Note to all Series III (ane earlier) LR owners. check your wiring loom where it runs through "P" clips. Some had no protection, so would (eventualy) wear through the wire and cause a short. For some odd reason, LR didn't fuse the obligatory lights on the SIII... I leave the rest to your fertile immaginations, but I was doing over 50 when I went to turn the light on, and the dash went up in front of me, as the switch welded closed...

You don't want that to happen in something like a Disco, with all that nice burnable plastic about the place....

Cheers n beers..

Dave B.

Reply to
Dave Baxter

Tell us exactly which year etc. and we may be able to help if you don't have the manual.

Reply to
Dougal

Thanks for all the helpful info, I'm away from home for a while now - it's an M reg, what's that in real terms.... 94 or 95. Before leaving home I had chance to check the battery voltage with the engine off/ running and it's seems to be charging so that rules out my early thoughts of it being related to the alternator (or does it??). When I get home I'll check out the Haynes diagrams and start pulling things apart - and hopefully come back to you all with the cause....

Many thanks

Mac

Reply to
oldMaxim

Usually if it's an alternator problem it will be overvoltage and the common symptom is bulbs blowing. Easily checked, just put a voltmeter on the output when it's running.

A fuse repeatedly blowing is usually a sign of a wiring problem somewhere generally chaffed insulation producing a short circuit down to earth. Bit of a pig to find as it requires careful examination along the loom. An alternative is to chop the suspect wire at each end and run in a replacement.

I had this problem on my alarm system some time ago - real pita.

Reply to
hugh

Though I've had alternators fail like that (on one ocasion actually boiling the battery!) Most fail in a way that they fail to charge, but do still work the warning light as you'd expect, and keep the tacho working.

If the tacho stop's (on a 200 or 300 Disco etc) then the alternator, is not, er... "Alternating"!....

If the warning lamp itself fails (that is, it does not light when the key is first turned) then even a good alternator will not start up correctly and fail to charge, resulting in the inevitable....... (They use the current through the bulb, to "kick" the thing into generating. Once it's doing that, it's self sustaining, so long as the electrical load is not too much, and the rev's are not too low.)

The trouble with "Alternators" is that they are deceptivly simple things, but can present and cause a range of symptoms, some of which can also be caused by other things...

The suggestion about identifying a bad wire (short to ground) and bypassing it is a good one, but it's still wise to find the actual fault point, as if one wire has chafed through, others might later. (Been there, got the T shirt etc!)

As earlier, work methodicaly and follow the diagram. For that era, though there are differences, much of the basic system was very similar, if not the same from year to year.

Regards.

Dave B.

Reply to
Dave Baxter

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