Defender TD5 Electrical Fault

a dodgy battery in the remote wont cause that......it will cause it not to start......
or it will not allow you to lock or unlock(cos the battery is dead and it wont work).....


what you are describing is a power problem.....you simply have a dodgy connection somwhere....
these are not easy to find......
have you checked your ecu to make sure your harness isnt full of oil......?
have you checked any of the earth leads to see if any are loose....?

if yes.....then just simply start the car...and wiggle some wiring around to see if you can replicate the problem....
until you can find what is causing it you obviously cant fix it.....




ON VERY RARE OCCASSIONS......
another thing that causes all sorts of "gremlins" is a dodgy alternator....
it will still work and charge and do what it is supposed to....
but will confuse the ecu in the process and throw up all sorts of faults on the dash....
very hard to diagnose cos nothing is wrong...it all works....
this is always the absolute last resort to electrical problems which are intermittent
and can never be found.....you could replace the whole wiring harness and every sensor....
and the ecu and the problem will still be there.....till someone decides to try an alternator.....
but dont bother with this...i just posted to let you know how much fun electrical faults can be.....

how dealerships diagnose problems is by swapping suspect parts or sensors with other vehicles
and seeing if the problem is fixed or transferred to the other vehicle....
the only way to do this at home...is to find someone who has the same vehicle and is willing
to lend you bits of it to try and find your problem.....

Yes, well hoping the problem was somehow the result of the dodgy remote was wishful thinking. The vehicle cut out about five times again last night.

Unfortunately one of those times was just as I stopped and, once again, everything went dead. Not lights, hazards, ignition, locks - nothing.
I thought maybe if I give the car a shake it might come good - and it did! Still had another couple of hiccups on the way home, but when they happen on the road the general movement & vibration must be enough to make whatever it is re-connect.

Now, my diagnosis is - it can't be a short circuit or I would have expected a blown fuse somewhere. It is killing ALL electrics which means either something breaking contact directly off the battery or an earth connection. Battery itself is ruled out - tested & fine. Battery earth/negative lead checked and secure to both chassis & transmission housing. Battery positive secure to battery but haven't gone any further yet.

I still can't believe with this kind of detailed info the dealer couldn't locate anything. It must be a major connection, and how many of those are there? Pretty much everything beyond the fusebox is on isolated circuits (including the ECU) so I would have thought this should narrow down my search abit. Beyond the basics (ie bits I can see) I just don't have any idea of where the Defender's wiring runs to follow a logical path to the problem.

I'm guessing now

Maybe the battery has an internal fault. A loose plate that's not connecting properly, or similar. A bit of movement giving an intermittent fault.

Anyway, its easy enough to swap out a battery & see what happens.

Regards
Max P

Quote:

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Originally Posted by solmanic

Yes, well hoping the problem was somehow the result of the dodgy remote was wishful thinking. The vehicle cut out about five times again last night.

Unfortunately one of those times was just as I stopped and, once again, everything went dead. Not lights, hazards, ignition, locks - nothing.
I thought maybe if I give the car a shake it might come good - and it did! Still had another couple of hiccups on the way home, but when they happen on the road the general movement & vibration must be enough to make whatever it is re-connect.

Now, my diagnosis is - it can't be a short circuit or I would have expected a blown fuse somewhere. It is killing ALL electrics which means either something breaking contact directly off the battery or an earth connection. Battery itself is ruled out - tested & fine. Battery earth/negative lead checked and secure to both chassis & transmission housing. Battery positive secure to battery but haven't gone any further yet.

I still can't believe with this kind of detailed info the dealer couldn't locate anything. It must be a major connection, and how many of those are there? Pretty much everything beyond the fusebox is on isolated circuits (including the ECU) so I would have thought this should narrow down my search abit. Beyond the basics (ie bits I can see) I just don't have any idea of where the Defender's wiring runs to follow a logical path to the problem.

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Surely the fact that it's killing everything must make it easy to fault find. Start at the battery with your voltmeter until you run out of volts?

I don't understand why your dealer can't do this. :huh: :huh:

Hi,

Had something similar in my TD5. Car started, then all died and that was it.

Found it was a loose earth. Near the battery box there is 3 or 4 nuts/bolts with earth leads bolted to them. One was loose and thats all it took to completley kill my car

Good luck

The challenge is catching it when the fault is occurring. Since it happens mainly on the road, and only for an instant, it is very hard to replicate.
The latest news from the dealer is that it may be the actual battery-earth lead itself. Not at any connection, but somewhere along the lead there is a break (how that happened who knows). We are waiting for confirmation after it has been driven around a bit with a new one.

if you were closer i would look at it for you.....

it shouldnt be that hard to find......
it seems to me all they are doing is driving it around and waiting for it die.....
which it never does for the repairman......

get it off them and just try what i told you....with it running.....start pushing...pulling....tugging....bending....flexing ....etc.....the wires you can see
starting from the battery and working back.....till you find one that causes your problem......

when it dies while you have your headlights on......do the park lights remain on.....
or do they switch off as well.....?

Park lights & everything - dead. I can see what you're getting at since the headlights go off with the ignition. No, it is definitely ALL dead. Hazard lights off as well. Still no word from the dealer to let me know if they are satisfied that the earth lead was the problem. At least they're making an effort this time. I don't know what they were doing (or not doing) whilst it was with them last week, but they had four days to find the fault. I picked it up and had it happen six times in the next 24 hours!

Unfortunately it's not just as easy as turning it on and jiggling wires. A few times when the power cut-out, when it came back on the car was immobilised and the alarm started going off. It appears that I still don't have the right security code to re-mobilise the vehicle. RACQ say this is a common problem as people often never need to use the code so no-one checks that it is the right one - and it often isn't. Consequently I'm happy to let the dealer work on it for a bit with the alarm going off every two minutes - keeps my neighbours happier.

Well the dealer thought they had found the problem - loose chassis connection on the main earth lead off the negative terminal of the battery. One of their guys wiggled it and things cut out and in. So they cleaned it up and re-tightened it - also checked all the other earth connections with no problems.

My wife picked it up and 20 minutes up the road, started cutting out again. Only a bit, and not enough to stop the car this time, but still the same problem. I took it out again this evening, and, you guessed it, another call for a tow truck.

It is back to the dealer in the morning and they are going to check a bit harder this time, but I am leaning more towards the loose battery plate idea. It occurs to me that if they were jiggling the main earth lead, it could have been jiggling the battery as well. I would think that if they have checked all the other earth connections, the battery is the only thing that has not been thoroughly scrutinised. I have passed this information on to them (I mentioned it the other day but when they thought they had found the problem I guess they stopped looking).

More to come I'm sure.

i like the idea of a loose plate in the battery.....
but wouldnt that just drop a cell.....reducing the voltage to 10v....

it should still keep running though cos the alternator is still running things.....
come to think of it....if it open circuits the battery....yes...that could do it....

want to borrow a battery.....?