I own a 1995 landrover disco, battery light has been showing for last couple of weeks on and off but only turns off for 2-3 minutes if it does, car need jump starting all the time, lights dim and flash bright. Ok so here is what I have done replaced my battery, checked voltage with volt meter I get 14-16volts when it is running and 12.8 when not running. So it doesn't seem to be the alternator, not the battery as I just replaced it thinking that was it, cleaned the terminals up thinking it was them what else could it possibly be? Can it still be the alternator even though my battery is reading 14-16volts when running? Also the car doesn't stop when running only doesn't like starting. Could it be something draining power? Although I would think that that would turn the battery light off after running for a while. Any suggestions before I take it in to the workshop? I would just take it there but live in the country and is a fair hike to the nearest auto shop.

 

14-16 when running and lights at various levels sounds like alternator and engine block don't have a good solid ground to the frame of the vehicle. You can verify this at home by clamping a battery jumper cable from the negative post ONLY to the engine. See if your readings change.

What I would want to see across the battery terminals is 13.8 - 14.4 volts, with just truck running. Turn on all the electrical items, lights, AC, fan on high, bone crusher stereo; and it should stay above 13.2 volts. If it drops below that suspect a bad diode in the alternator that is only allowing partial output in amps from alternator.

Some Discos have a bonding strap from rear of engine block to fire wall. And the negative battery lead snakes down beside radiator and ties to the frame. Any of these sort of connections can be corroded and cause voltage drop problems that vary all over the place.

 

Hmm thanks il check it tomorrow when it's light thanks il let you know how it goes

 

This forum never closes, and the sun never sets on the Rover Empire.

 

I have checked every possible connection I can find cleaned them all checked with volt meter they are all getting connection only thing I can find is there is a bolt missing In the fuse box which has a plate that the bolt goes through. There is current runnin through the plate but it doesn't flow through the bolt housing not sure if it should I will get a bolt and replace it. Still getting plenty of volts when car is started drops to 12.8 with absalutely everything running, stereo, a/c lights and windscreen wipers although it goes flat not running any accessories getting 16v+ sitting in neutral on and I still get the battery light grrr might have to take it to an auto electrician if I can't solve it soon can't really afford to fork out more than a few hundred though. All I want them to really do is diagnose it for me as if it is anything labour intensive I will do it myself. Will they just diagnose the problem for me?

 

Looks as though the alternator is only working sometimes is that normal ? Started it up 12.8 volts on battery, turned accessories on 12.1v turned them off let it run for a bit after about 4-5mins kicked up to 17v had nothing to do with thermostat as it hadn't opened up yet

 

bad diode in the alt