If your tach stops working or starts bouncing, you have low voltage. If your radio cuts in and out and the sound crackels, you have low voltage. And if your engine stops in the center of an intersection, you definently have low voltage. What to look for or how to prevent? Make sure after someone changes your serp. belt that it is on correctly. Mine was not installed right and I spent a year getting it finally fixed. If the system drops below 12.5 volts, no tach and wierd acting radio starts. If the battery drops and stays at or just below 10 volts, get your cell phone ready. I put a volt meter in the lighter socket and it was the best tool to finally understand thenutty things my Landy does. A starved battery can make it seem that it is the alternator, or low voltage could seem that the battery is shot. Or, the belt tensioner may be weak. I had three service guys from Land Rover almost wanting to replace the belt, alternator, the battery and the battery cables. All it was, the belt was on wrong. They even looked at the belt and did not see it was wrong. I took the alternator off and had it serviced to assure it was working properly, then I bought a brand name battery with a good warranty. I bought a Hayes service book (with pictures) and have done a total visual on the Landy to, hopefully, not go thru and more problems like I went through.

Happy Trails

 

The belt on my 94 Disco also was on wrong, and it took a few days for me to find a threading diagram. That was before I found the Haynes manual and the Rave CD.

 

Awesome info! Friday night my tach stopped working, then I noticed the alt light wasn't coming on when the ign was turned on?? I was kinda puzzled by the tach not working, thinking I had shorted wires somewhere?I've had the truck over a year and it's been OK up til now. I think my alt is shot as the light doesn't come on at all? I took the wire off the alt that goes to the light on the dash and ran it to ground, andthe lightcomes on. So I know the bulb is good and the wiring up to the alt is good. Anyone have any other input on why the alt/bat light wouldn't come on with the ign on and the engine NOT running? I have ~12.3V at the battery with the engine not running, about ~12.6V engine running. Any input would be greatly appreciated before I go and buy a fresh alt.

 

Go have a local auto parts store check your whole system, both the battery and alternator.
When tacks bounce or stopo, the alternator is bad, PERIOD.

 

I guess the forum was down for a couple of days as I couldn't get on here? Thanks for confirming my suspicions Disco Mike. The battery is good, in fact I drove the truck 50 miles home on battery power alone when the alt first died, at night, lights on. And it still cranked up like it was freshly charged. I took the main wire off the alt and connected a volt meter, it had 0.5V at idle and only rose to 1.5v at high RPM. I'll be getting a new alt! Anyone used those "souped up" alt's on ebay and such that put out ~120amps? Are they any good? I think the stock one is 85A?