Hey Guys!

Bit of an unusual problem i had today... I was sitting at the traffic lights when my stereo, cluster and aircon/fan all turned off for around 10 seconds then they just turned back on by themselves..
The engine kept running through this so ive got no idea what it was.....

When the cluster turned back on the SRS and Engine lights come on as per normal when starting the car up....

the only thing im thinking this could have been is my alternator finally giving up after around 2 months of the battery light intermittently turning on..

So what do we think is causing this guys? (its only happened once.)

Any ideas would really be appreciated!
Whippy.

Most probably the alternator, a guess a loose battery terminal ^_^ ?

definitely sounds like either your battery or alternator is about to die, or possibly both if it's been happening for 2 months. Get it checked out asap, the last thing you need is for the car to stop in the middle of traffic.

definitely sounds like either your battery or alternator is about to die, or possibly both if it's been happening for 2 months. Get it checked out asap, the last thing you need is for the car to stop in the middle of traffic.

. . . or have voltage fluctuations destroy some essential electronic component . . . .

the battery light has been coming on intermittently for 2 months and you've done what? please don't tell me you see it come on and think 'oh goody, I still have a battery' letting it slide for a week or two til pay day yea ok, but you've ignored it for 8 weeks, the car electrics cut out and now you worry about it??

I just love the "she will be right mate" attitude some people have when the alternator light starts coming on. lol As if it will fix itself!

I know that on the second gen alternator and earlier models this is quickly followed by the regulator blowing and some of the diodes giving out due to the surges of voltage and current produced when the brushes make and lose contact with the armature. Pretty much writes off the alternator.
I believe the 3rd gen alternator is a bit more sophisticated and is protected from such surges, but at least its a sign that you need to do something about it.

even though you have an alternator problem, i dont think that fixing the alternator will cure this problem because the engine was still running.
id have a look in the engine bay fuse box... particularly at the fusible links and main battery connections.
this problem could also be ignition switch related.
but fix the alternator ffs. before you do more damage to the car than its worth

A good while ago I was working on a KJ, with the centre-console out and working behind the climate panel -- doors open boot open and so on. The head-unit and climate were being fitted/re-fitted due to some issue I was tracing. Eventually, a head unit was put back in with an upgrade from 4-cd to 6-cd in-dash stacker and radio/climate panel re-fitted into the dash.... then the "test" phase.

Oh noes! The head unit was flicking on and off and never really powering up. "Bugger" I think, I must have broken something inside it and how lucky there is a spare head unit in the house. Which gets re-fitted (again)....... with the same tick-tick-tick power-on/power-off drama.

What had happened (I think) was that I had dicked-around so long with doors open and courtesy lamps on, possibly fiddlng with power windows etc - that the battery had run so low that it now had insufficient power to properly engage or maintain the connection in the relay for the dash etc. Battery on charger for a while and the issue never happened again. I shouted myself a new battery a short while later as the suspect one was in the car when I bought it, had a fair bit if age on it etc. Issue has never, ever happened again.

MOral of this tale? Maybe you alternator was so dodgy that it let the relay giving power to those accesories drop-out, and when alternator brushes made contact again the power kicked the rely in and led to power-up of dash etc. Either just a voltage drop for a moment which affected one relay but not all of them OR possibly the relay for those things is on the way out. If it happens again (prior to your high-priority alternator repair, which I recommend as well), you could check the relay in the engine bay box that affects those accesories - check that it doesn't feel hotter than any of the others as soon as you safely can after the problem recurs, and try swapping that relay for some other "minor" accessories (I'd avoid swapping with the ECU/engine one, for example).

What strikes me as odd here is the level of trust in charging lights on vehicles. I'm primarily a biker, and lots of bikes have massive charging issues (particularly mine) as they don't use a field-excited alternator which regulates the output voltage, but rather a permanent magnet rotor and stator coupled to a regulator/rectifier which shunts excess power as heat to a heatsink. If you then add in to the mix a small capacity battery, when the charging system fails you can be stranded before you know it because the fuel injection system drains the battery in short order. It's made worse by the fact that bikes run with their headlights on 100% of the time.

So anyway, one of the really common things bikers do is fit a voltmeter to their bike. There are literally like fifty different brands, some of which have LCD displays showing the voltage and others have multi-coloured LEDs that change colour as the voltage drops. At the first sign of a drop in voltage, you haul ass to the nearest servo and check that fecker out. The same thing should be done on a car too!!!

even though you have an alternator problem, i dont think that fixing the alternator will cure this problem because the engine was still running.
id have a look in the engine bay fuse box... particularly at the fusible links and main battery connections.
this problem could also be ignition switch related.
but fix the alternator ffs. before you do more damage to the car than its worth

Why is this, if the alt clags itself when running the engine will generally keep going until the battery dies, the battery and alt work as a pair but a car will run on either or if needed, more likely to run of battery as at idle there is not generally enough grunt in the alt to run the engine.

Replace the alt mate, if your light has been coming on for 2 months, I can not even see why this post was started lol

Had a similar issue today actually, got in the car this morning and the thing wouldn't start. Strange as it's a newish battery, sure enough alt/starter motor are probably still original but were working fine still yesterday.

Then remembered I had a similar issue months back that EGO helped me solve where the battery terminals had corrosion on them, sure enough after a quick sand the car fired first go.
Given the battery light has come on I dare say your alternator is on it's way out, but you can also check things like battery condition and terminals just in case.

Okay guys Thanks to all your posts im gonna get of my arse and fix the alt...

1, Should i go to an auto electrician and say "fix it"
or 2, go get a new regulator and slowly try to find the culprit...

Okay guys Thanks to all your posts im gonna get of my arse and fix the alt...

1, Should i go to an auto electrician and say "fix it"
or 2, go get a new regulator and slowly try to find the culprit...

Regulators rarely "fail", it's more likely the bushes are worn out. Pretty sure you can get kits to fix it, but if you're not sure how it's definitely something i'd be asking someone else to do. Last time this happened I just got a changeover alternator from an auto elec, was about $150 from memory. The bush kits were around $40 but I had no idea.

To do the alt properly, needs to be pulled apart, diodes checked, armature re surfaced ad then new bearings done. IF you do a new new reg, is like doing an oil change and using a second hand oil filter

Why is this, if the alt clags itself when running the engine will generally keep going until the battery dies, the battery and alt work as a pair but a car will run on either or if needed, more likely to run of battery as at idle there is not generally enough grunt in the alt to run the engine.

Replace the alt mate, if your light has been coming on for 2 months, I can not even see why this post was started lol

because if the charge of the battery drops to low then a car will usually drop dead, rather than continue running.
perhaps the alternator was over charging in this circumstance and the circuits were protecting themselves.
ive had a few 3g's in lately with bad connections in that fuse box, symptom presents as 14.x volts at battery but only say 10 volts inside, windows run slow, radio cuts out, etc.

because if the charge of the battery drops to low then a car will usually drop dead, rather than continue running.
perhaps the alternator was over charging in this circumstance and the circuits were protecting themselves.
ive had a few 3g's in lately with bad connections in that fuse box, symptom presents as 14.x volts at battery but only say 10 volts inside, windows run slow, radio cuts out, etc.

Well the battery is charging at 12.8 V so it is definatly undercharging...

Ive got the car booked in tomorrow to get a Brand new Alt installed for $350

i 100% agree with everyone. alternator has had it. i had the same problem a month or 2 back. get it fixed asap or you will end up broken down at the side of the road like i did

edit: didnt read your last post :P thats the same price i paid for mine.

Brand new Alternator / belts put on today... all good no battery lights or anything..

Brand new Alternator / belts put on today... all good no battery lights or anything..

Well done! Another happy AMC customer! A good price if its a NEW alternator!

Last time this happened to me I bought a recon job for $150, but that was a few years ago. It cooked itself quick smart and the sparky had to redo it under his 12 month warranty. lol

I wonder how much a wrecker wants for one? Just to pull apart to see what they look like inside. lol

Yeah it was $405 with the new belts added on as i thought he may aswell change them while his there... and that i dont know when they were done last ( had the car for 35,000kms...)
EDIT: yes it was a bread new alt

Yep, the belts aren't cheap. My TJ is due for new belts, the originals are 111,000 km old and starting to crack, so they do last for a long time. lol Sounds like this part of your car is good to go for a long time!

Yep, the belts aren't cheap. My TJ is due for new belts, the originals are 111,000 km old and starting to crack, so they do last for a long time. lol Sounds like this part of your car is good to go for a long time!

yeah htey arnt cheap at all....

the next one on the agenda is my timing belt... and with the car on 109,000kms its very urgent...