Electrical Problem?

[matthewpatz]

I have a 1998 Discovery, 130k miles. The lights throughout the vehicle has a steady flicker going on. I noticed it a few months but thought it was just my eyes playing tricks on me. It has become more obvious. this only occurs when the engine is running, turn engine off the flickering stops, the flicker slighting speeds up when given throttle but not very much. I just installed a brand new battery last week. I put a volt meter to the battery positive & Ground cables, with the engine running at idle and I get a reading of 14.28 - 14.37v it jumps back & forth almost in sync with the flickering of the lights. What can possibly be the problem? Alternator? A Ground issue? Any ideas would be very much appreciated!!!

I also just noticed that the front parking lights do not come on either.

Thanks
Matt

[antichrist]

Fluctuations in voltage will cause light flickering since the higher the voltage the brighter the light. Assuming all connections from the Alternator to the battery are sound, it sounds like the regulator is bad on the alternator. At any point in the diagnosis for the battery replacement did you disconnect the battery or alternator while the engine was running?

[matthewpatz]

No, I have not done that yet, I am planning on working on it this weekend to replace the window lift ECU and I was thinking of trying that test and seeing what happens. If the alternator is good what else could make that happen? What other test can I do if that doesn't tell me anything? I guess I could always run it up to the Advance auto or auto zone and have them test it.

There was a ton of corrosion on the positive terminal of the old battery. When I replace it I cleaned it and so far the terminals are still very clean., even though it's been about two weeks.

[antichrist]

Never disconnect the battery or alternator while the engine is running, it can fry the alternator diodes.
If the light's flicker only when the engine is running, it's probably the alternator or connection from alternator to battery.

[Trickymonk]

My 97 D1 was doing this and a battery/alternator test showed normal volt ranges. It was however, the alternator. A local independent LR master tech saw it and immediately said your alternator is going bad. I installed a new one and no more flicker.