My tachometer is intermitten , n the battery light comes on when the tach is not working?
What is causing this? Can i run the Land RoverDiscovery 1996?

 

Test your alternator and connections.

 

Check the 2 smaller connectors on the back of the alternator.

 

My battery light started glowing dimly, then the tach went out when the alternator failed completely. The tachometer counts pulses from the alternator to measure engine speed.

 

Your belt may not be installed right. Check that. Real common mistake. The most intuitive way to install a Disco drive belt is the wrong way. LOL. At idle it rotates the alternator over fine. At highway speeds it can be fine all summer, but start slipping now going into the winter where you might be using the heater fan and lights (where you didn't in the summer). It makes the tach go nuts and the rest of the gauges. Seems like it's being taken over by aliens ...like their ship is right over your vehicle as you drive (of course it IS above you ...you just can't see it bc they use a cloaking device). People test the battery and see it's not charging ...and they replace the alternator, then put on a rebuild with maybe a new belt. They forget how it's routed and look it up, routing the 'right' way this time ...and boom, it works. Sure enough it WAS the alternator all along (wrong). I bet there've been thousands of Disco alternators replaced that way. If this is the case, you probably have a glazed belt too, and double-check the alternator pulley ribs (slipping can wear out the pulley making the ribs sharp). New pulleys aren't that much (or weren't when I bought mine.

But of course it still could be the alt. Maybe the brushes are wearing out and right down to the nub. If it's an original Marnelli alt, you can buy a new back plate or brushes for not that much (check ebay or an alternator/starter store online) and rebuild it yourself. I did mine many yrs ago. I rebuild most of my vehicle OEM alternators. OEM stuff is generally a lot better quality. Plus you learn some neat things (there are good videos out there). You might want to double-check your body/engine grounds too before spending any money. It could be a bad ground. All electrical path goes through the ground so it's not trivial. Good luck! And watch out for those aliens!!!