i changed out the bat cable that runs from the battery to the fuse box and the bat light has not returned.. its been over a week now.
the cable was getting extremely hot and looked as if it was about to catch fire, the end was brittle and rubber coating was turning white..

 

I have replaced the relay an adjuster on the generator, now battery light burns constantly (pressure 14,3 V ).
jaglover922, specify please If water on the positive terminal sizzle that the wire is perfectly in order? It seems to me strange that the wire doesn't work, bat light lit up not always, and at repeated start of the engine light don't on. At a bad wire bat light would burn always?

 

what language are you translating from? seems to me there is a whole lot being lost in the translation.
maybe someone here speaks your language and can offer a better explanation of the issue.

seems you have tried different batteries.
Now if ANYTHING is getting hot enough to make water sizzle that is BIG PROBLEM.

you have been advised to change the cable a few times, but maybe you dont know what this means? CABLE=WIRE=LEAD maybe other terms too.

The X-Type alternator does not have a replaceable voltage regulator as far as I know. not sure what you just replaced? can you attach some digital pictures?

 

I have measured a voltage on the alternator terminals after that on the battery, there was same indications. It means that the cable is good.
voltage regulator: http://search.waiglobal.com/partnum.aspx?part=IN343

 

If something is getting hot, it means that the current is too much for the connection or wire..... voltage measurements are not going to show this very easily

 

The only way to show that a cable is offering too much resistance is to connect a multimeter from one end of the cable to the other and then pass a fairly high currently through the wire. In the case of our X-Types, if you connect the red lead of a multimeter to the output of the alternator and then the black lead to the positive post of the battery, even turning everything on electrically inside the car, you should see than 1.0 VDC doing this check. Personally, I would be looking for an upgrade/replacing the wire if I am seeing anything over 0.5 VDC. Think about it. Power (ie heat) is a function of voltage (in this case, voltage drop) and current. So, if you turn on a lot of electrical stuff inside the car (say, 100 amps worth which is really nothing more than the engine running, dash fan on high, rear defroster on, headlights, and wipers), you would be loosing 100 watts in the battery cable. Think about the amount of heat emitted by a 100 watt light bulb. That is how much heat your battery cable is releasing. Now, when you consider that the alternator can output up to 160 amps or you have a cable that is dropping more than 1.0 VDC, the amount of heat being emitted can rise dramatically.

The only way to test a battery cable without passing a large current through it is to get what is called a wheatstone bridge. Some may even call it a 3 wire/4 wire high accuracy resistance bridge. These are designed to read down to 0.001 ohms (some even more accurate). A standard multimeter at best will read to 0.1 ohm. I have them at work, but this isn't something that you would find at the local autoparts store. Possibly at a high end electronics repair shop, but, even then. They just aren't called for all that often. I only use them due to the sensitive nature of the electronics controlling a nuclear reactor.

 

I have change lead from the alternator to the battery. Now at the warm engine with switched off headlamps and aircon 13,45 V, when headlights and the air conditioner on 13,65 V. Battery warning lamp is off.

 

So... Is it fixed?

 

I have the same problem with my 2.2 diesel had alternator fitted light stayed on put old one back on, took it to jag specialist hes done tests recons it was because it wasnt a genuine jag part that was fitted still in shop waiting for jag alternator, any ideas?

 

After installation of one more lead from alternator to the battery, the car has passed about 215 miles, batt. warning light didn't burn. Today at morning all was ok, but later I star engine turn reverse gear and warning light has lit up! After engine restart, light has gone off. I dont know what to do !

 

Change the positive wire from battery to fuse box. That's what it was that cause the problem on our x type.

 

To under bonnet fuse box ?

 

Yes. It attaches from the patter post and connects into the fuse box from under it. Its about 1-2 foot wire

 

At engine working temperature, the battery negative lead is much hot than a positive lead.

 

Change them both, I got a cable from napa for $15 with tax...I'm changing the negative next just for piece of mind.
I had the battery light problem and headlights not powering up all the time.
New positive wire from battery to fuse box and problem is gone.
Wires wear out, jag used too thin of wires in this car...

 

Hi ghettomike re: the +lead from bat to fuse box, was there any visable damage to the lead when you changed it?

 

yes but it started off slow..
the rubber that covers the end of the wire where it attaches to the terminal was starting to look melted. finally it started looking crispy.
basically there was internal corrosion so power was still flowing but it was being funneled so to say. basically not enough power getting to the fuse box, computers etc. this causes the wire to heat up after a few hours of driving.
i changed the wire, headlight issue fixed, DSC occasional fault gone, and no more battery light.
under powering the cars electrical system can also lead to a electrical fire from the heat it causes.
im changing a lot of other opwer wires and ground wires in it this summer...for the price of them its worth it.

 

My battery light began coming on and off for a few days. I took it to Advance Auto to have them test the alternator. Guy said the alternator needed replacing, but I really don't trust those guys anyway.... especially since my 2003 x type only has 67K miles.

Then I read somewhere in a post that some guy was having the same problem and simply cleaned his battery terminals with a wire brush. So I found an old .22 rifle bore brush and some WD-40 and scrubbed the hell out of all my terminals, even the ground wire beside the battery and in front of the fuse box.

It's been about a week now and my light has not come on since.

However, after either me cleaning the terminals and hooking the battery back up or the Advance dude screwing with my car when my wife took it, my A/C did stop cooling (compressor kicking in?). I let the car sit for a day and then my A/C magically fixed itself. Kinda worries me. Anyone have a clue why the A/C went from freezing cold before the battery re-connect to inoperable for a day and then back to freezing cold? No problems now, but I'd like to preempt any future problems from occurring.

 

Just my luck... I post this and my battery light gave me a smooth **** you by coming on this morning. The negative terminal was fairly corroded when I cleaned it. Perhaps the wiring has corroded also? I'm thinking about replacing the negative terminal before I look at the option of replacing the alternator. Replace the cheapest thing first, right?

 

03 jag x type manual trans. the battery light is on. Bench tested the alternator and it tested good 8 times. checked all the wires i could, no corrosion after cleaning all connections. Goin out of my mind. voltage is the same at battery, starter, alternator, and dash. 11.9 volts is what is said at all 4 places. what tells the alternator to charge? Does the regulator itself? or ECM? Please help!!!!!!