Disco 2 Battery light - D2 TD5

This site contains affiliate links for which LandyZone may be compensated if you make a purchase.
tom1979

tom1979

Well-Known Member
Full Member
Posts
2,145
Location
East of England, UK
Randomly yesterday on my 2003 D2 my battery light stayed on. The battery is charging at a steady 14.3v. Not sure what to check first, is the light fed from the ECU/BCU?

1DEFB11A-3B47-44B2-8276-24F2BBE409B0.jpeg
 
Last edited:
The light is connected to the alternator's small connector through that square grey connector near the ECM so if the light was on while you've got that 14.3V reading might be a bad contact on the circuit cos the light comes on when it doesnt get feed but if the light comes on randomly while driving and you can't confirm the voltage can be an intermittent alternator failure too?
 
sierrafery said:
The light is connected to the alternator's small connector through that square grey connector near the ECM so if the light was on while you've got that 14.3V reading might be a bad contact on the circuit cos the light comes on when it doesnt get feed but if the light comes on randomly while driving and you can't confirm the voltage can be an intermittent alternator failure too?
Click to expand...

Thanks, I have a voltmeter plugged in permanently so hopefully would be able to see if it was not charging while driving. I will have a look at the connectors near the ECU. After leaving it running for a few minutes the light went out and did not come back on so I should think it is a connection somewhere. Presumably as long as it is physically charging normally it is safe to drive?
 
sierrafery said:
The light is connected to the alternator's small connector through that square grey connector near the ECM so if the light was on while you've got that 14.3V reading might be a bad contact on the circuit cos the light comes on when it doesnt get feed but if the light comes on randomly while driving and you can't confirm the voltage can be an intermittent alternator failure too?
Click to expand...
This one?
73EEF697-8BCF-4C82-934B-3AB303A1DB17.jpeg
 
That doesnt look square to me and i think it's closer to the fusebox than ECU, it's C0162 i meant, pin 2 brown/yellow wire
C0162.JPG
 
Last edited:
Did you check the small plug on the alternator too? anyway watch the voltmeter, if that shows above 13.5v while the light is still on you can drive it without fear but if the voltage climbs slowly as well then the alternator is on it's way out IMO
 
sierrafery said:
Did you check the small plug on the alternator too? anyway watch the voltmeter, if that shows above 13.5v while the light is still on you can drive it without fear but if the voltage climbs slowly as well then the alternator is on it's way out IMO
Click to expand...

I managed to get the plug off the back of the alternator earlier and using a power probe could reliably put the battery light on and off. To me this rules out wiring in the vehicle?

The battery light does seem to go off after a few miles of driving and doesn’t come back on until the vehicle has been left a while. I am wondering if it’s a sign the alternator is on it’s way out?
 
No, the alternator is perfectly fine........... right up until the moment that you really, really, really need to get home and its getting dark and you need your lights on and there's a traffic jam on the motorway and its cold and raining.
THIS is precisely WHEN it packs up. Up until this point it will be fine.
 
tom1979 said:
I managed to get the plug off the back of the alternator earlier and using a power probe could reliably put the battery light on and off. To me this rules out wiring in the vehicle?
Click to expand...
Unless it's a bad contact which reacts to vibrations... the relevant test is to watch the voltmeter while the lamp is on
 
DanClarke said:
No, the alternator is perfectly fine........... right up until the moment that you really, really, really need to get home and its getting dark and you need your lights on and there's a traffic jam on the motorway and its cold and raining.
THIS is precisely WHEN it packs up. Up until this point it will be fine.
Click to expand...

:D:D:D:D
 
sierrafery said:
If it's within the alternator the voltage should be down too when the light is on unless it's only on the lamp's path
Click to expand...

if I’ve got the right wire on the connector you showed I’m getting 13.1v on it, 14.4v at the alternator and 14.3v at the battery and at the fusebox.
0D20A2B3-52C0-420A-B92D-89B43BF1F471.jpeg
 
Looking at the wiring diagram that signal wire goes pretty much straight to the binnacle so I’m wondering if the problem is not the wiring but the alternator ?

C6AC5B96-1825-47BA-81E3-810A47D84B46.jpeg
5B4CA8CE-386B-4D3E-903B-5EB3C961BF8B.jpeg
 
If you get 13.1V on that NY wire while the warning lamp is on the problem should be the wiring or instrument pack cos the warning lamp comes on when the voltage on that wire drops below 7V
 
You must log in or register to reply here.

Similar threads

E
keyfob u/s
Replies
2
Views
339
Equinut
E
R
63 reg Disco TDV6 268bhp auto commercial, battery light on
Replies
10
Views
508
roythebus
R
D
D2 Oil pressure switch?
Replies
9
Views
881
Descapri
D
Andy Warren
Disco 2 Battery moniter
Replies
16
Views
1K
Andy Warren
Andy Warren
Henry.adams
Traction control problems
Replies
9
Views
720
Henry.adams
Henry.adams
Back
Top