Help please! '97 V8 5MT Discovery - purchased it when brand new. My battery wont charge no matter what I do. I have replaced the alternator twice and the battery is brand new and good (holds a charge fine). The alternators test fine when taken out. The tach has worked only intermittently for a couple of years. Voltage at both the alternator and battery are the same when running, i.e. lower than the ~12 volts at the battery when the Disco is switched off. The situation has gotten progressively worse over the last few years and now if driven more than a few miles the battery drains and the Rover dies.

* I have checked all the grounds that are known to go bad and they are clean and good.
If I could have missed one, please let me know.
* The belt and tensioners are fine.
* I have checked the continuity between the alternator mounting point and the negative battery post
and the positive alternator post and the positive battery terminal with an ohm meter. Absolutely good
connections.
* I have disconnecting the battery wire at the alternator and connect a multi meter between the body of
the alternator and the post for the battery output. The reading without the engine running is just over
2 volts. When running, the voltage is back to slightly less than just measuring the battery with the
motor off.
* All connections in engine fuse box are clean and test fine.

I have been working to solve the problem for several months. Please help!


PS, I posted previously but just realized it was the wrong forum. Sorry.
https://landroverforums.com/forum/di...81/#post577622

 

are the alternators new ? and are they "rover" alternators or chinese ? a remaned Rover alternator would be better than a cheap aftermarket one ......any chance that you have a buddy with a working disco you could swap the alternator out for a test ?

 

Is your no charge light lit? It's like a check engine light... should say "No Charge". On the dash.

 

Thanks. I was thinking just like you, swap the alternator to see what happens.... In some ways, I have tried three alternators. all Land Rover. None of the changes has effected charging at all. The first is the original with about 105K miles on it. I had it bench tested first and that showed it was fine. The second was from a Disco with ~135K miles. The "third" is the origional alternator that was rebuilt on site by a local shop even though the earlier bench test said it was OK. All function exactly the same.

 

Thanks. Sorry, I forgot to include that important piece of information... the no charge has never come on, except when the key is "on" and the engine is not running, e.g. before starting.

 

For my own knowledge, what does 5MT mean?

Next, a stupid question but I have not seen it mentioned here...is the belt routed correctly?

 

[QUOTE=WaltNYC;579149]For my own knowledge, what does 5MT mean?

Next, a stupid question but I have not seen it mentioned here...is the belt routed correctly?/QUOTE]

Thanks. 5MT is five speed manual transmission. Sorry, that is shorthand I have seen on other, non Land Rover forums. Yes, the belt is routed correctly (with air conditioner).

 

I'm not as familiar with disco 1 bit on the RRC there was a wire that put a 12v charge to alternator when the key is on. Without it the alternator won't charge. As I recall it could be jumpered

 

That was my thought too -- the signal trigger wire. I know people who have chased proper grounding for weeks on end and the problem ended up being a loose signal wire.

 

Excellent idea! I can test in a few hours. Is the signal wire the one with a clip on the alternator rather than studs and nuts? Simply run a test wire from the positive battery terminal to it while the engine is running?