Hello folks, I had my battery light come on whiles driving so I thought it may be the alternator or the battery but I had the battery checked with a multimeter and everything seems fine. The alternator was also intact. So I turned of the ignition and started the cat again and the light is off. Does this car heal itself or this is a real indication of an underlying problem. Any help is very muchh appreciated. Thank u

 

baffourg, the light only lights when the alternator output drops below that of the battery. So, yes, the light can go in and out. What I would tell you to do is to connect up a multimeter across the battery and position the multimeter so you can see it from the driver's seat. Now, with the engine running, turn on the headlights, rear defroster, and the A/C (max air flow). This should put a 65 amp draw on the alternator. If you see the multimeter drop below 13.3 VDC, then your alternator is starting to go and probably needs to be looked at. It may be possible that the power to the field is acting up (the field is controlled by the ECM) and if the wire is getting loose or somethign of the like, it can cause the output of the alternator to drop to zero, which will cause the battery light to light and have the car running off of the battery only.

If you need more assistance with this, let me know.

 

thanks thermo, i connected a multimeter it it the yesterday with the a/c running but not at full blast and also with the headlight on and it read 13.4, 13.5, then 13.4 and so on and so forth. the autoelectrician told me it could be what you are telling me but he also said it wouldn't be easy to remove the alternator, any ideas as to how to get it out? Again what should be done to it once its removed?

 

I would need to look at my car, but the alternator is packed in to the car pretty good. I seem to recall something about removing the front wheel well liner to get at it that way. First off though, disconnect your battery so you don't accidentally arc the wire coming off the back of the alternator. That can be a bit of a surprise if you know what I mean.

As for the alternator and what needs to be done to it, if you are having it rebuilt, the shop should put in new bearings, brush assembly, and rectifier at a minimum. It may be nice if they rewound the stator and rotor, but that isn't always necessary. But, if you are getting a rebuilt unit, all of this stuff should have been done to it already and all you need to make sure of is the battery is at full charge once you put the new alternator in. One of the quickest killers of new alternators is putting it in with a dead battery. Not having a fully charged battery causes the field winding to overheat and lead to its failure.

 

ok thermo, will keep that in mind. Will still wait for stepwise procedure on how to remove the alternator.

 

Here is the JTIS procedure, I see it makes mention of removing the A/C compressor!

 

this seems like a days job. will take her in this weekend. thanks guys

 

Oops, my battery light came on again but its amazing I just turned off the ignition and started the car again and its off. Could it be that the sensor is playing up cos I had it checked as thermos described and everything seems fine. Any other thing I should be considering?

 

Chris shame on you, i have mentioned this sooooooo often it should be a sticky in the xtype section. Xtypes suffer from battery cables that when they get old and hot underhood the resistance goes up and the voltage from the alt to the battery goes down. The cables get weven hotter from the resistance making it worse. Replace the +/- cables plus the link lead to the fuse box from the +. I just did 2 sets yesturday, including 1 with a new alt from a indy shop and still had the same problem the alt was replaced for. You can monitor battery voltage through the instrument packs 'engineering mode" now lets see who has paid attention in class and can tell him how to do this

 

Signal stalk, press in and hold while starting the car or just put it in position 3. press repeatedly after it goes into test mode until you see what you're looking for, it runs diagnostics in some so if you press the stalk it moves on.

What do I win Brutal?

 

a $75 discount off my diagnostic charges in future
and what you failed to mention is youre looking for bat and the displayed voltage like 14.2 etc
bat 13.8

 

Where is the signal stalk. Is it the indicator stalk/high beam stalk?

 

baffourg, yes, it is the stalk on the left side of the steering column.

 

Thanks y'all I will try that and let you know how it turns out

 

@Brutal - Your advise about changing out the cables worked perfectly for my car. My car was getting the On and Off, On and Off senario with the Battery light. Your logic is onpoint with the heat of the cable causing the resistance to change. Plus my car is seven years old and the cable connections to my battery were looking a bit rough.

 

I have changed my battery cables and so far no battery light on the dash. I also noticed that one of the earth terminals was loose so I had it tightened. I pray it doesn't come on again. Thanks y'all

 

Good to hear your battery light solved , mine is flickering sometimes and goes away when I accelerate ,I noticed that last week lol

 

I have a 2006 X-Type 3.0 with 65,000 miles. The red battery light playing hide and seek with me :-). To try to fix it, I did the following:
1. Replaced the battery
2. Replaced the alternator (bought from a Jaguar dealer for $700)
3. Replaced BOTH - and + battery cables
Once the battery light comes on (which is 1-2 times every other day), I pull over and turn the car off for about 2 minutes. When I restart, the battery light is off.

Any ideas, experts?

 

Replace the link lead to the fuse box from the +. monitor your battery voltage through the instrument packs 'engineering mode".

 

Hi Baffourg,

You state, "Replace the link lead to the fuse box from the +."

In case you know of any, can you suggest some places online from where I can order the link lead online?

Regards,
Jimmy