96 Buick century headlights

buick
century

#1

I have a 96 Buick century that the headlights will dim during exceleration and stay dimmed till I let off the throttle. Or they will essentially blink bright and dim at highway speeds. The weired thing is, at idle, the lights are fine! Help, it’s driving me insane


#2

Have your charging system tested. And your battery. The lights aren’t getting the full 12VDC.

It has to do with the greater current being drawn to push the arc through the higher cylinder pressures when the throttle is opened. Yours is insufficient to both operate the engine and the lights when the engine is under load.


#3

I had the system checked, they guy advised me that the battery was running low so I replaced it. Never said anything about the alternator.


#4

He probably only tested he battery. It’s common.

Give it another shot at a different shop. You might have a weird reaction to a high resistance corroded battery connection too, but my money is still on the alternator.


#5

Allright. I will give it another shot. I’ll be back and let you know what I find


#6

I just thought of another longshot possibility. Check the serpentine belt. and the tensioner. It might be slipping under load.

Alternators work by drawing magnets through a force field. When under load, the coils draw more current through the field windings and it becomes significantly more difficult to spin the alternator…at the very time when the engine needs more juice. More load increases the possibility of belts slippage.


#7

Also check the battery cables and connections


#8

Those side battery terminals are notorious for corrosion under the rubber boots. Check them carefully.


#9

Besides the above, you might ask your mechanic if he could wire up a temporary volt meter for you to observe the voltage at the battery terminals while you drive. If the battery voltage lowers in certain circumstances, that would provide a clue to what is going on. When the engine is running the voltage would typically be around 14.4 volts. When the engine is stopped it would be around 12.6 volts.