battery light staying on [Archive] - Mitsubishi Lancer Register Forum

battery light staying on

b6lee
27-02-2009, 19:05
havin trouble with my battery light staying on while driving.

first of all it started flickering but then it just stayed on and hasnt gone out since.

took the car to my local auto electrician who said he thought it must be the alternator, he got a reading of 15.8 volts. so i got a replacement.

replacement was fitted today but did not cure the problem.

my tuner, who is 2 hrs away which is to far to drive it thinks maybe evo scan might come up with something but i don`t no anyone local to try this so can anyone help ?????

lee

grayw
27-02-2009, 19:33
Do you have a multimeter? The checks for battery and alternator are very simple. Evoscan won't tell you anything different than a multimeter.

b6lee
28-02-2009, 12:50
Do you have a multimeter? The checks for battery and alternator are very simple. Evoscan won't tell you anything different than a multimeter.

but my local auto electrician has already tested everything he could........maybe ?

grayw
28-02-2009, 14:32
What was the idle and fast idle voltage?

b6lee
28-02-2009, 15:42
he said he got a reading of 15.8 so thought the alt must be over charging which i had changed but battery light is still on

grayw
28-02-2009, 16:05
15.8v is way high, maybe voltage regulator.

b6lee
28-02-2009, 16:08
where is that ?

jhfozzy
28-02-2009, 16:28
where is that ?

The regulator is built into the back of modern alternators, so would have been changed when you had a new alternator fitted.

You could have damaged something having 15.8v shoved through the car.

The battery light is a simple beast, not much can go wrong with it.

One side has 12v fed to it via the ignition.

The other goes to a seperate (most of the time) output from the regulator (bolted to the alternator).

With the ign on and engine stopped. this output is at earth potential, earthing the lamp and bringing it on.

When you start the car, the output goes to 12v (really 14 odd but don't worry about that). Both sides of the lamp are at 12v and the light goes out.

Simple really :lol:

Fault finding.

Is the lamp dim? as the diode in the combi display can fail and short causing a dim lamp.

Other than that, it's a faulty alternator again, we get a few in work, really annoying.

b6lee
28-02-2009, 17:22
The regulator is built into the back of modern alternators, so would have been changed when you had a new alternator fitted.

You could have damaged something having 15.8v shoved through the car.

The battery light is a simple beast, not much can go wrong with it.

One side has 12v fed to it via the ignition.

The other goes to a seperate (most of the time) output from the regulator (bolted to the alternator).

With the ign on and engine stopped. this output is at earth potential, earthing the lamp and bringing it on.

When you start the car, the output goes to 12v (really 14 odd but don't worry about that). Both sides of the lamp are at 12v and the light goes out.

Simple really :lol:

Fault finding.

Is the lamp dim? as the diode in the combi display can fail and short causing a dim lamp.

Other than that, it's a faulty alternator again, we get a few in work, really annoying.


the lamp is as bright as can be all of the time.

the problem started when i started the car for the first time in nearly a week, the light was on continusly so checked the belt and battery conections and alternator conections and all were fine but light was still on. i nerverously took car out for a quick run around the town then when i got back the light had gone out so i took the car out again but found that every time i put my foot down the light would come straight on. even reving the car when stationary the light would flicker or stay on.

this happened on a couple short trips out in the car then it just decided it would stay on constantly.

then had the alternator changed but it has stayed the same whith the battery light on constantly :shake:

b6lee
01-03-2009, 14:51
such a nice day but cant go out and drive :shake:

grayw
01-03-2009, 15:08
Can you disconnect the battery and check the voltage across the terminals?

b6lee
01-03-2009, 16:06
no cos i dont have a multi meter.

what you thinking ?

grayw
01-03-2009, 16:09
It can only really be a battery or charge system fault, someone like Grants or Brain Carroll would be the people to ask.

b6lee
01-03-2009, 21:10
:shake:

grants
01-03-2009, 21:12
Somebody call :D

Check a 7.5A fuse (No.7** brown in colour) under the bonnet. It only supplies the alternator voltage sense terminal, if it has blown the alternator may/will provide its maximum output voltage (> 14.4)

**

Between a red 10A fuse and green 30A fuse

:)

b6lee
01-03-2009, 21:33
thanks, will have a look

:smthumbup

b6lee
02-03-2009, 19:21
Somebody call :D

Check a 7.5A fuse (No.7** brown in colour) under the bonnet. It only supplies the alternator voltage sense terminal, if it has blown the alternator may/will provide its maximum output voltage (> 14.4)

**

Between a red 10A fuse and green 30A fuse

:)

fuse checked today but found no problem. also with the engine running and someone watching the light i had a good route round checking electrical conections but still not got to the bottom of the problem :wallbang:

jhfozzy
02-03-2009, 20:57
replacement was fitted today but did not cure the problem.

Just to confirm, the light is staying on, but is the voltage still 15.8v??

b6lee
02-03-2009, 21:29
Just to confirm, the light is staying on, but is the voltage still 15.8v??

yea thats right

lee_r_one
03-03-2009, 00:11
sounds like iffy alternator to me or poss bad connection from alternator to battery by whatever rout it takes if goes via starter motor check there as cranking can allow a connection from high current demand yet can still have poor connection for charge current worth a look ?

cormac79
03-03-2009, 00:16
Was it a new alternator or did he recondition the original for you - if reconditioned the problem still may be the voltage regulator....

I assume they wouldn't change this part if a recondition was done?

lee_r_one
03-03-2009, 00:17
even if recon should replace if faulty

b6lee
03-03-2009, 19:41
thanks for your thoughts people :smthumbup

spoke to electrician again today and i was slightly wrong about the voltage the alternator is putting out, it`s actually 15.2 not 15.8, oops my mistake :D

i said to him about trying a different alternator but he didnt think it would be worth it cos he seems to think that ecu plays a part in what the alternator output is there for the ecu might need looking at but his computer system does not work with my car.

can anyone local help me out with this ? :smthumbup

replacement alternator was taken from an evo 8 and is thought to be in good order.

b6lee
07-03-2009, 01:03
car is going to mitsi this coming week, hopefully they can find the problem :yawn:

b6lee
20-03-2009, 20:46
update time,

car went to local mitsi dealer last week and they checked the wiring the alternator and the battery and so they said the alternator is at fault and its cooking the battery.

so i ordered a recon alternator in exchange for my original one.

had it fitted today and guess what, THE LIGHT IS STILL ON AND STILL CHARGING AT 15.8 volts :wallbang::wallbang::mad:

somebody please help me !!!!

jhfozzy
20-03-2009, 22:51
update time,

car went to local mitsi dealer last week and they checked the wiring the alternator and the battery and so they said the alternator is at fault and its cooking the battery.

so i ordered a recon alternator in exchange for my original one.

had it fitted today and guess what, THE LIGHT IS STILL ON AND STILL CHARGING AT 15.8 volts :wallbang::wallbang::mad:

somebody please help me !!!!

It could possibly be a faulty cell / sulphation in the battery, have you got a battery you could get hold of to try in place of yours? (doesn't have to be exactly the same)

That's the only other thing I can think of.

These alternators are self regulating, if three alternators are all overcharging, it's got to be something else.

Hope you get to the bottom of the problem soon, post up if you get any success.

John. :smthumbup

b6lee
21-03-2009, 13:22
It could possibly be a faulty cell / sulphation in the battery, have you got a battery you could get hold of to try in place of yours? (doesn't have to be exactly the same)

That's the only other thing I can think of.

These alternators are self regulating, if three alternators are all overcharging, it's got to be something else.

Hope you get to the bottom of the problem soon, post up if you get any success.

John. :smthumbup

connected a different battery up to the car today but still no change :shake:

b6lee
31-03-2009, 18:43
the roumor has it that it could be the front ecu relay which is located in the fuse box

can anyone back this up ?

i have one on the way from local mitsi dealer so hopefully this will be the end of my problem and car will back on the road for regional meet/rolling road day at power station on saturday :smthumbup

V16 dom
31-03-2009, 21:09
the roumor has it that it could be the front ecu relay which is located in the fuse box

can anyone back this up ?

i have one on the way from local mitsi dealer so hopefully this will be the end of my problem and car will back on the road for regional meet/rolling road day at power station on saturday :smthumbup

hi lee you have a pm, dom.

Brian Carroll
03-04-2009, 05:20
Been away from here for a while but my twopenneth since you've basically ruled out the alternator and battery and checked that fuse that Grants suggested is it would come down to prodding around seeing what voltages you have at the alternator itself and in particular checking that the connections to the wires that go to the engine ECU are intact and operating - that would be my approach off the top of my head. I've been involved in discussions on here before where charging voltages have been quite high and certainly in the 15v regime under certain conditions and considered normal - IIRC. I know from my Ford Focus that it has what they term a SMART charging system and under certain conditions you see similar voiltages up to about 16v (one of the reasons headlamp bulbs have a short lifetimeon the Focus). That said, there's obviously a problem and the only active component you haven't tested in that circuit is the ECU which has a role in the regulation of output voltage from the Alternator.

The fuse that Grants highlighted is on the battery sense wire and is how the alternator regulator knows what voltage is being put out, that's also an area to check, if that fuse is intact as you say is the circuit intact? Is there battery voltage on the Yellow wire at the alternato, if not there's a break in that circuit.

There is a fairly comprehensive alternator diagnostic procedure in the Workshop Manual downloadable from here as well but that requires some test equipment. Whilst the approach of replacing bits until the problem goes away is a common one, a proper diagnostic process by someone who can read a circuit diagram is really the way forward as it's costing you money to keep pursuing dead ends.

b6lee
03-04-2009, 23:09
Been away from here for a while but my twopenneth since you've basically ruled out the alternator and battery and checked that fuse that Grants suggested is it would come down to prodding around seeing what voltages you have at the alternator itself and in particular checking that the connections to the wires that go to the engine ECU are intact and operating - that would be my approach off the top of my head. I've been involved in discussions on here before where charging voltages have been quite high and certainly in the 15v regime under certain conditions and considered normal - IIRC. I know from my Ford Focus that it has what they term a SMART charging system and under certain conditions you see similar voiltages up to about 16v (one of the reasons headlamp bulbs have a short lifetimeon the Focus). That said, there's obviously a problem and the only active component you haven't tested in that circuit is the ECU which has a role in the regulation of output voltage from the Alternator.

The fuse that Grants highlighted is on the battery sense wire and is how the alternator regulator knows what voltage is being put out, that's also an area to check, if that fuse is intact as you say is the circuit intact? Is there battery voltage on the Yellow wire at the alternato, if not there's a break in that circuit.

There is a fairly comprehensive alternator diagnostic procedure in the Workshop Manual downloadable from here as well but that requires some test equipment. Whilst the approach of replacing bits until the problem goes away is a common one, a proper diagnostic process by someone who can read a circuit diagram is really the way forward as it's costing you money to keep pursuing dead ends.

thanks mate i will see if i can get some of your thoughts checked out :smthumbup

oh and for the record i tried changing the main ecu front relay but still no change :shake:

V16 dom
04-04-2009, 00:07
thanks mate i will see if i can get some of your thoughts checked out :smthumbup

oh and for the record i tried changing the main ecu front relay but still no change :shake:

You have a pm. dom

Brian Carroll
04-04-2009, 04:04
thanks mate i will see if i can get some of your thoughts checked out :smthumbup

oh and for the record i tried changing the main ecu front relay but still no change :shake:

My opinion for what it's worth is until you have someone who knows what they're doing and can interpret a circuit diagram just take a multimeter to the connections on the alternator and see what they're doing you're going to be getting into this 'try this' scenario - find a good autoelectrician - not someone who keeps offering failing advice at a distance or tells you something then walks away from the problem. I find it very disappointing that you've had someone out to look at it and they walked away, they should be ashamed of themselves. Lets not talk about the Mitsubishi dealer as they'll have only stuck a diagnostic tool on it, which wont reveal problems at this level. If I was a gambling man I'd say the battery sense wire (the yellow one) has a fault on it, but doing it from a distance is difficult.

Unfortunately there's a lot of people out there in whatever trade who want the easy bits of the work, wouldn't we all?

b6lee
05-04-2009, 18:56
My opinion for what it's worth is until you have someone who knows what they're doing and can interpret a circuit diagram just take a multimeter to the connections on the alternator and see what they're doing you're going to be getting into this 'try this' scenario - find a good autoelectrician - not someone who keeps offering failing advice at a distance or tells you something then walks away from the problem. I find it very disappointing that you've had someone out to look at it and they walked away, they should be ashamed of themselves. Lets not talk about the Mitsubishi dealer as they'll have only stuck a diagnostic tool on it, which wont reveal problems at this level. If I was a gambling man I'd say the battery sense wire (the yellow one) has a fault on it, but doing it from a distance is difficult.

Unfortunately there's a lot of people out there in whatever trade who want the easy bits of the work, wouldn't we all?


is there a way i can try do this myself ?

ie running a wire from the alternator to the oppisite side of the fuse with the fuse removed ?

V16 dom
05-04-2009, 19:04
Lee have you checked earth continuity as you may have a paralle earth, meaning you have the +12v from the alternator to the battery but have a high resistance on the neg ie loose earth from car body to the engine frame thus giving you a bad earth connection keeping the bat light lit on the dash.
:D

grants
05-04-2009, 19:39
Not sure whether it's been mention earlier but check for corrosion on a 10 way (black approx 40 x 25mm in size) connector - B14 on the diagrams - hidden under the battery tray, or there abouts

:)

V16 dom
05-04-2009, 19:46
A very simple way to check is to use a spare jump lead, fix one end to the engine ( in a safe position ) and the other on the body structure or neg of the battery, then just see if the battery light goes off on tic over and use a muilti meter to see if the battery charging voltage has dropped to 14.4 ish volts. DO NOT DRIVE THE CAR WITH THE JUMP LEADS ATACHED JUST WHEN PARKED.:smthumbup useing the jump lead as a tempery earthing strap.

b6lee
12-04-2009, 14:22
HEY HEY HEY CAR IS NOW FIXED !!!!! :D

Nice bloke from mitsi came out the other night and took the car away and spent a bit of time checking through the wiring and found that one of the wires had a break in it. so car is now back to how it should be so yea i went out last night and done in a tank of v power :D :D :D

thanks people for your help !

V16 dom
12-04-2009, 20:42
HEY HEY HEY CAR IS NOW FIXED !!!!! :D

Nice bloke from mitsi came out the other night and took the car away and spent a bit of time checking through the wiring and found that one of the wires had a break in it. so car is now back to how it should be so yea i went out last night and done in a tank of v power :D :D :D

thanks people for your help !

Nice to hear that its all sorted mate, did sound like a earthing type of fault tho, all the best Dom:smthumbup