need help my discos dead!

ok so it happened like this my 94 3.9 v8 disco has been ok till about a week ago when the revo and speedo stopped working plus the battery light was on whilst working after a few miles they started up once home tryed to lock the motor and the fob doesnt work so tryed my spare one no joy a few days later still running fine get back home try the fob maybe 10 times and the doors lock think nothing more till i try to unlock the next day and none of fobs work can still get in via the key but alarm is going and immobiliser wont let me fire it up after much stress and slamming of doors and bonnet find out about the alarm ecu (17vt on this motor) so i unplugged the bugger over night plugged it back in next day and voila fobs work ignition works runs fine big smug grin 4 hrs later try to start her up nothing the fobs still working central locking all that crap turn key and not a sausage just silence now ive been scratching my head all day which im sure has lost some fluff today and cant figure anything out getting it towed to the garage is not a route i want to take any enlightenment would be received with many thanks

is there a bit i can hit with a hammer to get it going

If your battery light comes on and speedo & tachometer aren't working then it's quite likely your alternator is FUBAR.

What I would say too .. Alternator dying/dead, therefore battery getting deader. Give the battery a good charge, at least overnight and see if it improves.

1 charge battery
2 start vehicle
3 check alternator is charging by measuring voltage across battery terminals while engine running. You should get 13-14 volts, anything under 12 volts suggests alternator is dead.

Like any job you need to be methodical and eliminate the obvious/simple things first

puddlejumper said:

If your battery light comes on and speedo & tachometer aren't working then it's quite likely your alternator is FUBAR.

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^^^^ +1

nice one ill give that a go i did try it on the jump leads but that didnt do anything also i can turn the head lights on full and theres no dip after several seconds would that suggest the battery isnt flat i did have a look at the fuses under the bonnet and the big alternator fuse had alot of oxidisation inside it maybe worth changing it out also tryed the ignition with the lights on to see if they dimmed and they didnt suggesting there is nothing at the starter(this is what haynes said im no mechanic)

pulled the battery out to charge the bugger see if that works fingers crossed ironically the battery had a sticker saying recharge due sept 15 dunno how old the battery is but they had mystic meg doing the dates dont know if that would affect it we will see tomorrow

ok so ive charged the battery overnight put it back in and wait for it.........nothing all ive achieved on that one is purchasing a battery charger and blocking the radio with a code i dont have any other ideas guys willing to try pretty much anything at this stage

Butty1984 said:

ok so ive charged the battery overnight put it back in and wait for it.........nothing all ive achieved on that one is purchasing a battery charger and blocking the radio with a code i dont have any other ideas guys willing to try pretty much anything at this stage

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Question is : Did the battery take the your overnight charge? if you suspect u have an iffy battery it wouldn't.

discool said:

Question is : Did the battery take the your overnight charge? if you suspect u have an iffy battery it wouldn't.

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im pretty sure the battery is good the full battery was lit on my charger and my head lights still turn on and stay strong with no fade

have you had the cover off the alarm controller to check for dry joints?

shoes4pigeons said:

have you had the cover off the alarm controller to check for dry joints?

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cant say i have what would i be looking for also is that the alarm ecu in the passenger footwell

yeah the one in the footwell.

you say you unplugged it and left it for a bit and it worked for a few hours?

dry joints can be really obvious and they can also be really hard to spot. if I were you I would do a google image search for dry joints and get an idea of what you are looking for and then take the cover off and look. alternatively if you can take a good quality photo of it I will take a look but u wouldn't hold your breath over a photo.

I had to repair my window controller that sits next to the alarm controller due to dry joints and water ingress. the mud flap mount had rotten and was allowing water to fall onto it.

could be as simple as that?

I agree with everything the other guys have said, it does sound battery related but if you have eliminated that then we need to think outside the box

shoes4pigeons said:

yeah the one in the footwell.

you say you unplugged it and left it for a bit and it worked for a few hours?

dry joints can be really obvious and they can also be really hard to spot. if I were you I would do a google image search for dry joints and get an idea of what you are looking for and then take the cover off and look. alternatively if you can take a good quality photo of it I will take a look but u wouldn't hold your breath over a photo.

I had to repair my window controller that sits next to the alarm controller due to dry joints and water ingress. the mud flap mount had rotten and was allowing water to fall onto it.

could be as simple as that?

I agree with everything the other guys have said, it does sound battery related but if you have eliminated that then we need to think outside the box

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spot on ill have a look at that then lucky ive not bolted the bugger back in yet due to how hard it was getting it out ill let you know how i get on nice one

good luck,

mine is completely disconnected and bypassed, it was when I got the car. I can only guess the reason for this was water damage and dry joints like I found on the window controller.

the guy I bought the car from was happy not having any opening windows, maybe he was also happy to not have an alarm and that's why he had it bypassed???

The single button fob security ECUs that 94MY disco's have, have been known to have functioning issues but easy are to replace if a fault was found, but keep away with your soldering iron as there are more intricate electronic components in a security ECU than the windows ECU box of relays.
Have you tried just using the key in the drivers door as that will also immobilise/remobilise your engine via a micro switch at the rear of the lock which also has been known to fail.
Also, if the engine is cranking but not firing try a wire link between battery + and ignition coil +

^^^^^^^ god yeah don't just go poking about in there if you don't know what you are doing.

just see if you can see any problems. if you can, then find a professional to take a look at it for you.

ok so i think ive narrowed it down to the alarm ecu more so the immobiliser element of it as ive for a second time left it unplugged for a day or two and upon plugging back in she fires up first time so i had a thought that if i tried locking and unlocking on the fob it may not fire up which it didnt but the alarm and locking work fine so its a case that the immobiliser does not turn off after being activated ive checked inside the box for dry contacts but cant see anything so it must just be a faulty part is there a way of getting rid of the thing altogether as im not that fussed about having it there

Still waiting for answers # 17