Battery Warning Light - permanently on !
Discussion
Hi Team 
Just as I'm going through last-minute checks before joining guillotine
in Belgium next week, my Battery Warning Light has come on - permanently.
It came on yesterday, just normal driving around, although hot outside.
Managed to get her home in 20 minutes and the motor started again, there, without probs.
Tried her again today and started no probs but light still on !
Had a search on here and most peeps tend to go with "Big Fuse".
Some have said "2 minute job" and others have said "a real b
d".
My baby is a 2001 4.5 and, for the last 12 years, I haven't even been able to see the
offending article, let alone replace it.
Anyone got any tips on how NOT to make this a gigantic rebuild
Ta !
PJ
Just as I'm going through last-minute checks before joining guillotine
in Belgium next week, my Battery Warning Light has come on - permanently.
It came on yesterday, just normal driving around, although hot outside.
Managed to get her home in 20 minutes and the motor started again, there, without probs.
Tried her again today and started no probs but light still on !
Had a search on here and most peeps tend to go with "Big Fuse".
Some have said "2 minute job" and others have said "a real b
d".My baby is a 2001 4.5 and, for the last 12 years, I haven't even been able to see the
offending article, let alone replace it.
Anyone got any tips on how NOT to make this a gigantic rebuild
Ta !
PJ
Edited by Mr Cerbera on Wednesday 4th July 06:36
The first test to carry out is to disconnect the alternator warning light wire and switch the ignition on...there should be no battery light showing
The second test to carry out is to measure + & - voltages at the alternator for any volt drops, be sure that the + & - are good
If those two tests prove to be checking out ok the alternator is faulty
I really shouldn't ask this but.....Have you checked the fan belt?.....Sorry I had to
The second test to carry out is to measure + & - voltages at the alternator for any volt drops, be sure that the + & - are good
If those two tests prove to be checking out ok the alternator is faulty
I really shouldn't ask this but.....Have you checked the fan belt?.....Sorry I had to
Penelope Stopit said:
I really shouldn't ask this but.....Have you checked the fan belt?.....Sorry I had to
Although our friend is perhaps being a little perverse, there is actually the possibility that the alternator belt is slipping enough to stop the alternator chargingI had something vaguely similar happening with another car, except with the PS belt
Belts can slip without squealing - I honestly didn't appreciate that
In my case a PS belt was slipping under load, but not squealing, due to oil contamination
Alternator belts are probably much less prone to slipping due to their multi rib structure, but don't rule it out
ukkid35 said:
Penelope Stopit said:
I really shouldn't ask this but.....Have you checked the fan belt?.....Sorry I had to
Although our friend is perhaps being a little perverse, there is actually the possibility that the alternator belt is slipping enough to stop the alternator chargingI had something vaguely similar happening with another car, except with the PS belt
Belts can slip without squealing - I honestly didn't appreciate that
In my case a PS belt was slipping under load, but not squealing, due to oil contamination
Alternator belts are probably much less prone to slipping due to their multi rib structure, but don't rule it out
I have never liked asking anyone if they have checked the belt as this is a bit like asking "do you know what you are doing", although it is something often overlooked by many
Jhonno said:
Check the voltage on the battery when running..
^ This. Only takes a sec and will tell you if it’s a false alarm. Voltage should read 12v with engine off and 13.5+ at 2k revs.If the light is on for no reason it’s possible the oil warning light and battery lights have swapped wiring, in which case possibly the wire has come off the oil pressure switch.
FarmyardPants said:
^ This. Only takes a sec and will tell you if it’s a false alarm. Voltage should read 12v with engine off and 13.5+ at 2k revs.
If the light is on for no reason it’s possible the oil warning light and battery lights have swapped wiring, in which case possibly the wire has come off the oil pressure switch.
If the wiring was the wrong way round and the battery light came on and stayed on permanently it would mean there was no oil pressure and the engine would have disintegratedIf the light is on for no reason it’s possible the oil warning light and battery lights have swapped wiring, in which case possibly the wire has come off the oil pressure switch.
If the wiring was the wrong way round and the wire had come off the oil pressure switch the battery light would not illuminate
Big fuse. Do your wipers move really slowly. Does the tacho jump around
The original big fuse is mounted on the back of the engine. Remove the scuttle panel and look down behind the coils. As said, you won't see it's broken as it fractures by the tab. Getting the cover unclipped can be a bh.
Use a small socket on a long extention to undo the nuts slightly to ease the fuse out. If it's metal, wrap it in tape if you haven't disconnected the battery to stop your tool shorting on the engine/throttle link etc.
Sometimes they come slightly too long to fit, so it's worth just filing down the bolt slot slightly to make it fit.
The original big fuse is mounted on the back of the engine. Remove the scuttle panel and look down behind the coils. As said, you won't see it's broken as it fractures by the tab. Getting the cover unclipped can be a b
h. Use a small socket on a long extention to undo the nuts slightly to ease the fuse out. If it's metal, wrap it in tape if you haven't disconnected the battery to stop your tool shorting on the engine/throttle link etc.
Sometimes they come slightly too long to fit, so it's worth just filing down the bolt slot slightly to make it fit.
Penelope Stopit said:
......
I really shouldn't ask this but.....Have you checked the fan belt?.....Sorry I had to
Well, I'm glad you DID ask coz I can't find it !!I really shouldn't ask this but.....Have you checked the fan belt?.....Sorry I had to
I can't believe that the alternator is located BEHIND the AC pump.
Where the hell does the drive come from ?
I know that I'm stupid but surely it can't be here..... Can it !!
That'll mean that I'll have to take the fuel injection system apart to change the belt.
Shirley not ??
Holy Dingbats !!
Edited by Mr Cerbera on Wednesday 4th July 17:47
Top pic, Yep, it's in there, alternator just visible.
Bottom pic, the alternator and its mounting bracket have been removed, you're looking at the drive pulley (which is driven by the timing chain).
I don't think Penelope realised that it's not that easy to check the drive belt on an AJP, as others have suggested it's far simpler to put a voltmeter across the battery and check for an increase in volts when the engine is running.
You must have seen/ touched your 100A fuse when you worked on your coils/ HT leads recently, it should be just behind them.
Bottom pic, the alternator and its mounting bracket have been removed, you're looking at the drive pulley (which is driven by the timing chain).
I don't think Penelope realised that it's not that easy to check the drive belt on an AJP, as others have suggested it's far simpler to put a voltmeter across the battery and check for an increase in volts when the engine is running.
You must have seen/ touched your 100A fuse when you worked on your coils/ HT leads recently, it should be just behind them.
TwinKam said:
I don't think Penelope realised that it's not that easy to check the drive belt on an AJP
Mmmm Penelope had no idea whatsoever about how difficult that engine is to work on, Penelope also suggested -"The first test to carry out is to disconnect the alternator warning light wire and switch the ignition on...there should be no battery light showing
The second test to carry out is to measure + & - voltages at the alternator for any volt drops, be sure that the + & - are good"
Penelope was not even close on this one and apologises for such a way off the mark suggested diagnosis
Mr Cerbera, good look in finding the problem, please excuse my ignorance......Nice engine
Penelope Stopit said:
If the wiring was the wrong way round and the battery light came on and stayed on permanently it would mean there was no oil pressure and the engine would have disintegrated
If the wiring was the wrong way round and the wire had come off the oil pressure switch the battery light would not illuminate
If the wiring was the wrong way round and the wire had come off the oil pressure switch the battery light would not illuminate
not necessarily.The pressure switch sits in the vee. If the wire had come off there's a good chance the terminal is resting on the block.
Penelope Stopit said:
TwinKam said:
I don't think Penelope realised that it's not that easy to check the drive belt on an AJP
Mmmm Penelope had no idea whatsoever about how difficult that engine is to work on,
Penelope Stopit said:
Penelope also suggested -
"The first test to carry out is to disconnect the alternator warning light wire and switch the ignition on...there should be no battery light showing
The second test to carry out is to measure + & - voltages at the alternator for any volt drops, be sure that the + & - are good"
Neither of these suggestions are really viable unless you remove the fuel rail which involves a lot of disassembly (second pic) and you can't run the engine in that state anyway."The first test to carry out is to disconnect the alternator warning light wire and switch the ignition on...there should be no battery light showing
The second test to carry out is to measure + & - voltages at the alternator for any volt drops, be sure that the + & - are good"
Penelope Stopit said:
Penelope was not even close on this one and apologises for such a way off the mark suggested diagnosis
Mr Cerbera, good look in finding the problem, please excuse my ignorance......Nice engine
That's ok.Mr Cerbera, good look in finding the problem, please excuse my ignorance......Nice engine
Paul, let us know what the voltage is across the battery with engine running, assuming it still starts
Edited by FarmyardPants on Thursday 5th July 09:27
FarmyardPants said:
If the light is on for no reason it’s possible the oil warning light and battery lights have swapped wiring, in which case possibly the wire has come off the oil pressure switch.
This is very interesting, I commented - If the wiring was the wrong way round and the battery light came on and stayed on permanently it would mean there was no oil pressure and the engine would have disintegratedI was commenting on your above post
You didn't mention about the wire could be shorting on the block
Only a subtle addition on your part hey.....but a massive difference
Edited by Penelope Stopit on Thursday 5th July 09:44
FarmyardPants said:
That's ok.
Paul, let us know what the voltage is across the battery with engine running, assuming it still starts
Before Starting: Volts across Battery (to engine earth) = 12.33VPaul, let us know what the voltage is across the battery with engine running, assuming it still starts
When idling ~ 900 rpm = 11.96V
From my 'standing next to wing' view I can't see the alternaror pulley moving
BUT
I can't see the engine pulley moving either
Am gonna try to see summat more with an endoscope cam.
Have taken my necktie off (just in case).
Wish me luck
Mr Cerbera said:
Penelope Stopit said:
Mine was "Sho Shin", the nearest translation of which is "Beginner's Mind".
i.e. Always ask questions. Without questions there are no answers and no mental growth.
I'm with you Penny
Yes, Sho Shin is definitely the way forward.
Once upon a time I visited the Benetton F1 Factory and the person showing my group around mentioned "CAD", In the middle of a very busy office full of engineers I asked out loud......What does CAD mean? I did blush a little when I received the answer. I wish more people would ask and learn rather than pretend to know but not knowing something isn't macho is it
I'm with you Mr Cerbera
Edited by Penelope Stopit on Thursday 5th July 15:50
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