High beam headlights not working

Hello,

It sounds like you have a a headlight control switch that is out. Here are the headlight wiring diagrams so you can see how the system works.

Test for power output of the switch to confirm the failure.

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

Check out the diagrams (Below)

Please let us know if you need anything else to get the problem fixed.

Cheers, Ken

Forget the fuses because this is an intermittent problem that doesn't act up all the time. A blown fuse won't work sometimes.

Lets start with the two most common symptoms, the drained battery and the flickering head lights. GM has had a real common problem with their generators that were redesigned for the 1987 model year. Due to their design, they develop huge voltage spikes that can destroy the internal diodes and voltage regulator, and can interfere with computer sensor signals.

Normally you can do the first half of testing the charging system by measuring the battery voltage with an inexpensive digital voltmeter. It must be between 13.75 and 14.75 volts with the engine running. With GM's systems though that is not sufficient. When one of the six diodes fails, all you'll be able to get is exactly one third of the generator's design value for current, but battery voltage will usually still be okay. 30 amps from the common 90 amp generator is not sufficient to meet the needs of the electrical system under all conditions. The battery will have to make up the difference until it slowly runs down.

Also with one bad diode, one phase of the three-phase output will be lost, and that results in very high "ripple" voltage. The second half of the tests requires a professional load tester. Those will measure full-load output current and ripple voltage. Those two tests will identify a bad diode. You can't do that any other way except to draw conclusions from the symptoms you have. If it is determined the generator needs to be replaced, you must replace the battery at the same time unless it is less than about two years old. The battery is the key component in damping and absorbing those harmful voltage spikes, but it loses its ability to do that as it ages and the lead flakes off the plates.

The dash problem might be related to a charging system problem too because the instrument cluster is no longer the simple and reliable set of gauges and lights it used to be. It's now a very complicated and unreliable computer module, and as such, it is susceptible to those voltage spikes.

Does the car start properly

SORRY FOR THE DELAY. USE A TEST LIGHT TO CHECK FOR POWER AT THE HEADLAMP SOCKETS. IF POWER IS THEIR REPLACE THE BULBS. IF NOT REMOVE THE LOWER DASH PANEL AND CHECK FOR POWER AT THE DIMMER SWITCH. IT'S ON THE LOWER PART OF THE STEERING COL. YOU WILL SEE A ROD GOING TO IT MOVE WHEN YOU TRY TO DIM THE LIGHTS.3 WIRES GO TO IT.1 HAS POWER GOING TO IT WHEN YOU TURN THE LIGHTS ON. THEN CHECK TO SEE IF THE POWER GOES TO THE OTHER 2 WIRES WHILE YOU OPERATE THE DIMMER SWITCH, START HERE

Now u will need to ck. The ground. Hook the test light to the positive post on the battery. Then u need to push into the black wire at the socket. The test light should light.

Suspect faulty multi-function switch

Check splice connector 102 under battery tray known problem due to corrison will interupt ground for LOW and DRL

I'M SORRY I CANNOT BE MORE HELP. IMMA JEEP CJ KINDA GUY MOSTLY

MAYBE THIS DIAGRAM WITH HELP YOU. IT'S FROM "MITCHELL I", AND IT'S EZ TO READ

IF YOU CANNOT SEE IT WELL---TELL ME

I CAN INITIATE A WAY TO GET YOU THE ORIGINAL DOWNLOAD WITHOUT YOU BLURTING OUT YOUR EMAIL ADDRESS IN OPEN FORUM!

HERE IT IS

THE MEDIC

Does engine start good? Test charging system.

Not a sensor, all related to wiring at or near the headlight switch on steering column though. Will need to pop open steering column to inspect the wiring to see if something is damaged or loose.