The wiring for these headlights is complicated. The body control module (BCM) controls whether the headlights should be on or off depending on the ambient light sensor readings. Your headlight switch should override this if switched to on - if it doesn't do this, the headlight power relay may be faulty.
The daytime running lamps (DRLs) are also controlled by the BCM and a DRL relay, also controlled by readings from the ambient light sensor. If they will not come on, the DRL relay may be faulty.
However, the root cause could be a fuse, faulty light sensor, headlight switch, or BCM. I would start by checking the fuses and checking/replacing the two relays.
SOURCE: 1997 Chevrolet Headlight problem
We had the same exact symptoms right down to the clicking noise under the dash. A friend who is a mechanic provided all the wiring diagrams, etc and when we pulled the dash we found that there was another enclosure behind the dash.....we stopped there.......
....waited a few days, did some research and decided since a replacement headlight switch was about $50.00 the easiest route was to to swap that out hoping it would fix the problem....was also a very easy installation.
Turns out that fixed the problem. Good luck!!!
SOURCE: headlights alternate on and off left and right daytime/high beam
although the underhood relay panel is common, I'd check your headlamp bulbs first, these are cheaper than the fuse box. The daytime running lights work off the high beam circuit, thus, a blown highbeam bulb could be the culprit, the fusebox solution was more common on 2001 and up modles, although it's a definite possibility.
SOURCE: low beam headlight /daytime light are not working
It's on the driver's side. Remove all the plastic & it's in there.Big rectangle, black box,about 1.5" thick,lotta wires.
SOURCE: Low beams and daytime runners do not work. High
headlights have burned out on the low beam side, replace both headlights, should fix your problem
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