I don't know about the D1, but it's probably a similar setup to the D2 -- the frame of the alternator is the ground and there is one heavy wire going to the battery via the fusebox. In addition there is a small wire that connects to a terminal on the back of the alternator -- that's the one to check.

 

Thanks! Yes, there is one heavy wire going to the main fuse. There are two smaller wires. One with a clip and one attached with a nut. My guess is the one with the clip is the one to jump but it would be nice to receive a confirmation.

 

Check the rave to be sure I know which one it is on a RRC but no idea on a D1 and don't want to assist in a "insurance fire" lol

 

ldaddy, do you have the electrical trouble shooting manual with all the diagrams?

https://www.cubbyusercontent.com/pl/...0Discovery%20I

wmlj970e.pdf = workshop manual....aka: RAVE. The bible for these trucks

etlj970x.pdf - electrical troubleshooting manual.

hl01561n.pdf - owner's manual... highly optional

look for etlj970x.pdf

page 77....

 

This a great help! I purchased the general factory manual when the Disco was new, almost 20 years ago. I could not find detailed electrical information though. With this, I am on track to getting the Disco running again. Thanks!

 

Thanks again for all your suggestions! I have studied the electrical manual and performed the trigger wire jump test.... still no success.

Please provide any additional ideas or, if there is a shop in the SF Bay Area that might solve the problem, I would be up for that too.

Below is a summary of the problem and what has been tried.

Problem:
'97 V8 5MT Discovery - purchased new.

Tach worked intermittently for years, progressivly getting worse. The tach not working is seen as a sign that the alternater is going out. Note: the tack worked better in dry weather and be out more in the wet.

The "charge light" in the dash is not lit.

Finally, the Disco died, i.e. would not run because the battery drained so much while driving that it would not support essential engine functions.

Solutions Tired:
*Alternater
Tested fine at a speciality alternater/generator shop. Purchased a second "Land Rover" alternater at Pick N Pull. Also had the oritional alternater reubuilt at the alternater shop.
- Outcome: No change in condition between the origional alternater, the rebuilt alternater (both test fine) or the extra Land Rover alternater.

*Battery
Holds a charge fine. Purchased a new one anyway. Also holds a charge for weeks / months ... as long as the car is not running.

*Belt Routing
Belt routed correctly alternater turns perfectly with correct belt tension.

*Tests
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.

All grounds that are known to go bad are clean and good.

I 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 are absolutely good.

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 slightly less than just measuring the battery with the motor off.

All connections in engine fuse box are clean and test fine.

I jumped the ground between the alternater body and the battery, the alternater positive outpute and the battery and the signal trigger wire on the alternater and the positive terminal on the batter. None made any difference. Note, the signal trigger wire is the smaller terminal with a nut - not the clip.

 

I wish I had the magic cure for you , but it still sounds like a bad or weak alternator,if the ground cables are good, and the cable from the alternator to the battery is good, it ought to be charging the battery with 13.5 to 14.5 volts at idle, do you have a buddy (GOOD buddy) with a rover that you could coerce into swapping some parts ?

 

I agree with X8, this line doesnt make sense - 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.

It should read at least high 13's up to 14.4V when running, and switched off i would expect low 13's immediately until it settles in the high 12's.

 

Before I was "given" my Disco ($600.00!), the previous owner had the same problem - he was replacing the lifetime Checker alternator every month! I talked him into a new NAPA alternator and told him to verify battery charge also when swapped. Every time he came in to me the battery was already down from driving with the bad alternator. His battery was a new NAPA (Johnson Controls), but was always high 11's - low 12 volts. He came back with the new alt and same problems - battery was down to 11.8 - so I warrantied the battery, new was above 12.6 and presto, charging and has ever since. I was always told at GM and NAPA that the trigger must see 12.6 or higher before it will start charging and that is what made all the difference. He had also run new grounds and his replacement battery cables are still not what I want, but even with all that, Ive never had a problem - I did put an Optima Red in - just because.
Verify your beginning battery voltage as being at least 12.6 or higher before starting and keep us posted. Russ