I have a 1985 Toyota Landcruiser (FJ60) with some electrical/charging system problems (I think). The truck starts fine, runs fine, but while running the needle on the battery gauge on the dashboard bounces up and down randomly. At night, this makes my headlights dim out and brighten up randomly, which makes me look like I am flashing my high beams onto on-coming traffic. After a good run, usually more than 20 miles or when the engine heats up to normal, and I go ahead and shut the engine off, the car won’t start as if the battery was low on charge. If I let it cool down for about an hour or so (being in hot and sunny Arizona this does not help the situation), it would restart. I have put in a new battery and the alternator and starter are fairly. Does this all sounds like it could be the voltage regulator? Please help.
Cesar in Phoenix.
A faulty voltage regulator would be the most likely cause. Don’t know if that one has an external or internal regulator but if internal, then the whole alternator needs replacing. I had that once on a rebuilt alternator. NAPA said it checked out fine but finally replaced it anyway under warrenty and flickering went away. You have to be very suspect of the current rebuilt alternators out there now. Some are just plain junk. I only use Delco rebuilt ones now.
It does sound like a voltage regulator problem. Battery is probably never charged well, and because the resistance is slightly higher in the starter when it is warm, the battery is not strong enough to turn a warm starter.
1980-1987 Land Cruisers came with two different alternators, some with voltage regulators attached to a 55 amp alternator, and some with external voltage regulators on a 45 amp alternator. Look at the pictures in an on-line parts vendor website and you will be able to tell which one you have.