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Discussion Starter #1
Well, another odd one. Today the little red battery light came on. I have studied the RAV, and it says it indicates a "no or low charge condition". The owner's manual states it indicates "a fault" in the charging system. I also determined it is triggered by the ECM.

Here's the thing...the voltage at the battery with the engine running is 14.16v, which indicates the alternator is putting out just fine. With the engine shut down, the battery voltage drops down to 12.67v...which is also what I would expect. The car shows no OBD codes. I drove the car all day after checking the alternator output, with high blowers and all the electric heat running, and the battery voltage did not drop at all...so I have no doubt that the alternator is charging.

So anybody know what the deal is? Is there a particular connector or fuse that could indicate a no-charge condition when the alternator is charging?
 

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Is the light on when you measure the 14.16v? Seems it should not be on if so.
 

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Discussion Starter #3
Yes, the light is on while I am reading 14.1v.

I had a thought today, that maybe the problem was the opposite, as in too much charge. I had my daughter rev the motor while I checked the battery voltage. No luck...a steady 14.1v at all RPM's. I did notice, however, that when she let off the gas, the voltage fluctuated down to 13.6v for a couple seconds.

I am wondering if the fluctuation is what is tripping the light. It is off for the first 10 minutes of driving in the morning, and then comes on. That leads me to believe there cannot be a bad connection or fuse, as then the light would never go off. I'm afraid it will take swapping the alternator with a new one to check out the fluctuation theory. Bummer.

I have been studying more about our charging system. Pretty interesting. It is all self contained inside the alternator. The interesting part is there is an output from the alternator to the ECM, to tell the ECM to raise the idle speed if it is unable to carry the charging load at a reduced idle. How cool is that?!

Anyway, I'm likely going to just replace the alternator, as there is nothing else that could be wrong, unless the ECM is bad. I doubt that...
 

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Interesting. My 'charge light' popped on today as well, but at least my car had the good manners to run until the battery went flat, then cut out. I got it to my local independent by running it with a 'booster pack' connected to the battery jump start terminals and sure enough, almost no charging from the alternator.

That's fine, but the alternator is exactly 368 days old, i.e. just over a year, but the local parts store who supplied it are warrantee-ing it anyways. I'm pretty sure I heard the compressor in the trunk running during the 'no or low charge' light period. Is this triggered by low voltage (like all the other codes I saw, such as Air suspension inop, trans failsafe, HDC inop etc) or did the compressor cause the voltage issue?

D2
 

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Discussion Starter #5
These do some strange things when the battery gets low. I think that is what you were experiencing. The alternator is 150 amps, so I have no doubt the compressor did not overpower the alternator. I'm sure it did speed the battery going flat, though.

I've been driving mine for 3 days now with the light on. I think that shows it is charging, so I don't know what's going on.
 

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Take a look at these threads for some more info, and diagnostic path, I'm feeling lazy and don't want to type.

http://www.rangerovers.net/forum/6-range-rover-mark-iii-l322/56769-failsafe-mode-battery.html

http://www.rangerovers.net/forum/6-range-rover-mark-iii-l322/47916-battery-fully-charge-but-engine-wont-turn-over.html

http://www.rangerovers.net/forum/6-range-rover-mark-iii-l322/60450-battery-light-wont-go-away.html

Check the voltages at the main fuse box, my guess would be either a blown fuse 5, or a failing ignition switch.
 

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Discussion Starter #7
Thanks Dave. That gives me some hope that it may not be the alternator. I'll check the voltages in the morning. Couple quick questions, if you don't mind...

Dumb one...what's the "IP" you mention in the posts?

And, if it turns out to be the ignition switch, can the contacts be cleaned or is it a throw away item?
 

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IP = Instrument Pack

I have never taken the switch apart, so I'm not real sure if the contacts are accessible. I can say that I have not had an issue with the contacts for the connector, it has always been internal.

Also, at least one of those links has a bunch of information that has nothing to do with the battery light.
 

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Good info guys, thanks. Don't want to hijack this thread, so I'll just hitch a ride here if that's OK. I'll do some tests in the morning, car is on charge over night. Should add, my battery is BRAND NEW. Maybe been on the car a month or so.

D2
 

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Discussion Starter #10
IP = Instrument Pack

I have never taken the switch apart, so I'm not real sure if the contacts are accessible. I can say that I have not had an issue with the contacts for the connector, it has always been internal.

Also, at least one of those links has a bunch of information that has nothing to do with the battery light.
Thanks, Dave. Pertinent or not...it's all good stuff!
 

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Discussion Starter #11
I checked the voltages at the fuse panel. They were all at least 14v with the charge light on. That has to rule out resistence in the ignition switch. Back to bummer.

The light was off twice today...both on initial start up with the car cold. It stays off about 10 minutes and then comes on, both times at a steady cruise on the highway at about 2500 RPM. Once it comes on, it stays on continually until the car cools down again. Heat leads me to believe a bad semiconductor in the regulator maybe.

I have to assume it is an intermittent fault inside the alternator. So here is another question. I find alternators online from $150 to over $450. I also see with previous posts that many new alternators only last about a year and die. Do any of you out there have good/bad stories to relate about different rebuilt alternators to help me choose a decent one?

Thanks...

Oh, I had a huge problem trying to find a ground inside the cabin to check the fuse voltages. I don't know if you guys have looked, but pretty much everything in the cabin is plastic! I finally realized the cigarette lighter has a conveniently located ground. I'm sure most of you already knew that, but I'm a little slow...
 

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Discussion Starter #12
Well, no responses, so here's where I am. There are new alternators available made by LAectric. (that is not a typo!?!) For a range of $215 to $589. I decided to avoid the aftermarket, although it may be fine. I have ordered a rebuilt Bosch unit for $189 off EBay, with no core charge. The local LR dealer price...$2880. That is also not a typo!

The charge light randomly goes on and off now. The head lights do not dim when the light comes on, so it is still charging, but who knows what's going on.
 

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You should check the wire connectors where the wires are bolted together,
there are about 4 of these connection points,
any loose sections could cause the issue,
also check the battery terminals ,
and the explosive charged connector on the pos terminal
 

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Discussion Starter #14
Thanks Stan. I have looked for voltage drop across all those points, except the alternator stud itself. I am afraid to try to get to that one with the engine running. The voltages are all within .01v across all connection points. I am truly at a loss, as the alternator is charging. The only items left are the alternator itself with some kind of internal fault (like a weak diode), and the ECM. Of the two possibilities, I rate the alternator as a higher likelyhood.
 

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With good charging voltage to the battery, and to the fuse box through the ignition switch, and the light still on, you're looking at either the controller(regulator/diode pack in the alternator) or the wiring to it. Also, very small chance of the IP being failed, and causing the light to stay on (very unlikely).

You can purchase just the regulator for the alternator, but I have never tried to replace it separately from the complete alternator, and with the price of a reman Bosch unit(good quality part, haven't had any issues with them) I would probably still do the whole unit, even if it were just the regulator at fault.
 

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Also buy a new O-ring seal before you start. The old one may be "okay", but if you're replacing the alternator, don't skimp on the coolant O-ring seal that goes around it. Hopefully the bolts that secure the alternator won't also need to be replaced.

And of course, while you've got it torn-down this far, think of anything else that you may want to take care of as periodic maintenance, like the belts, coolant pump, fan clutch, vanos seals / upper timing cover seals...
 

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Good info guys, thanks. Don't want to hijack this thread, so I'll just hitch a ride here if that's OK. I'll do some tests in the morning, car is on charge over night. Should add, my battery is BRAND NEW. Maybe been on the car a month or so.

D2
New alternator fitted, charge light extinguished! Now have no radio power (see separate thread please)

D2
 

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Discussion Starter #18
The rebuilt alternator arrived. Also received a couple extra o-rings and the special wrenches to remove the fan coupling. All I need is for the weather to cooperate on a day I'm off.

Of note, we've been driving the car daily all week and it is still charging fine, although the battery light is still lit after 10 minutes of driving every day. Go figure?!
 

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Before you open everything up, I think I missed the 'after 10 minutes' before. Just want to make sure on this, but did you check the voltage of the fuses vs battery while running, once the light had come on?
 

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Discussion Starter #20
Yes I did. Fuses 1-6 all had 14.15 volts with the light on. The battery posts (not the cables going to the posts) show 4.17 volts. The large fuses in the fuse box show 4.16 volts.

The tests show everything is good, both with the light on or off. The light always comes on above 2000 RPM, so all I can guess is there is a transient issue with the alternator. Occasionally it will go off while driving, or even flicker a few times and then go back on.
 
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