1984 Other Nissan Models Battery gauge drops on load, going

84STANZA

MEMBER
1984 NISSAN
4 CYL
FWD
AUTOMATIC
80,000 MILES

When an electrical load is put on the system (headlights, brake lights, windshield wipers, blinkers, etc.) The battery gauge drops significantly. At normal operation with no load it will hover a little below 18v. With a load put on it it will drop as low as 10v and below, where the alternator belt starts slipping and squealing. New alternator belts and tightening them will fix the slipping temporarily, but the gauge still drops drastically under load. I have been through two belts in as many months. The battery is newer and strong and does not need charging. The alternator has been replaced at least once before, and the same problem existed then also. Car starts and runs fine otherwise. A little note: after the last belt broke and was replaced, the turn signals now stay on and do not "blink" when engaged. I'm not worried about the turn signals not working as much as finding the root of this problem. Crossed wires somewhere in the electrical?

1 Reply

ZACKMAN

MECHANIC
4,202 POSTS

As for the turn signal doesn't blink, you need to replace the flasher unit (usually) under the dash.

Your alternator is probably fine, but the voltage regulator needs to be replaced. With the engine running electrical loads, your alternator should turn in between 13.5V to 15.9V. Out of this range, your voltage regulator is bad.

As the old belt broke, I would also check the bearing on the alternator, making sure the pulley turns freely and smoothly and no bearing noise.