Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
Hello & Welcome,
Do you have a test light or multimeter that you can do some testing with?
Let's start with the basics. Here is a schematic that shows the DRL relay and a couple of fuses. If you could use your meter to make sure there is power at both sides of each fuse, that would be great.
If the DRLs are working, I suspect that the fuse shown on the right is good.
By the way, what relays did you check and how did you check them?
Did you check for power at both of the fuses I highlighted, with your meter?
If so, the next step would be to check for a good ground at the lights themselves, or the sockets, that are shown in the schematics. This would be the Pink wires for the high beams and the Dark Green wires for the low beams.
Please let me know what you find.
OK - You said in your first message that the daytime running lights were working.
Is that correct?
Do the low beams work?
I would check the ground wires at the headlight bulbs themselves.
If you are using the positive source as your reference (connecting your "common" lead of the meter to 12 volts), that means that power is making it through the light bulbs, but there is no path to ground.
The ground is provided through the Hi / Low beam switch, and then the Headlight relay, as shown in the schematic below.
When you try to select the high beams, does the indicator come on in the dash?
What bothers me is that the DRLs are not working AND the headlgihts are not working too. That kind of tells me that the DRL relay is not turning on, and that is controlled by the Body Control Module (BCM).
If the DRL relay was closing, then both high beam lights would be connected in a series configuration, and the 12 volts would be divided between them. That is what the schematic shows. I am wondering of the BCM is functioning properly.
I am also assuming that you are using the light switch to try and turn on the headlights - is that correct? That also sends a signal to the BCM which is supposed to close the headlamp relay.
You also have a "flash-to-pass" function of the hi / low beam selector, which the schematic shows would bypass the headlamp relay. This is kind of a middle position on the switch. Does that work (flash the hi beams)?
Yep - this is freaky.
Let me just verify that we are talking about the same relays.
Here is the diagram for the DRL relay location.
Here is the diagram for the Headlamp Relay location. I/P means Instrument Panel (or dash).
As an experiment, you could use a jumper wire to connect one of the headlight ground pins (pink or dark blue as mentioned above), to make sure the bulbs actually work.
Let me know about those relays.
No problem. I should be here tomorrow.