Ha - Johnny - You treed me! 3:20 pm for both of us.

 

6:20 for me...

 

Pull headlight fuses 13 + 12 then check for voltage on the positive side of the fuse terminals. Does the intermittence occur? This is the virgin supply for the headlight system. Should the intermittence be here proceed backwards towards the battery. Next, check the voltage flow on to the rotary headlight switch, on the line side and the load side. Steady voltage flow at the headlight switch, then move on to the high low beam switch. Check for output voltage at the high low beam switch. Some cars come equipped with an automatic hands-free optical high low beam sensor that should be checked too.

13 volts reference is normal. With the car running and the alternator at peak the voltage can be higher. The fuses are just an electrical link they are not a source of significant impedance. Corrosion on fuse panel connections can indeed cause a restriction in voltage flow.

This is the process a shop would conduct. Based on results by direct wiring the headlight unit appears to be functioning properly.

A comprehensive wiring schematic would be helpful. Perhaps someone out there has one to share.

 

This has been keeping me up at night. I started looking at circuits. One thing I am sure of now, there are no traditional plugin relays built into the light circuits. Instead, they're integral in the front body control module. As I was looking at the LS RS main/dip circuits something stood out that could be a possibility given your symptoms of flickering LS HLs, and that is the LS HL ground circuit.

Grounds are typically laid out in close proximity to the device served and surely enough, there is a ground circuit lug on the LS inner fender well. If the grounds for the LS HL are loose or corroded, then it can very possibly cause the flickering you describe. Problem is, I looked at mine, and w/o disassembling anything I could NOT find it. I can easily see the RS Ground lug for the RS HL. So, I suggest you try to find the LS ground lug and look for any issues there. Here is an illustration. The ground wires you need are G00036 and G00037. Both will be brown wires with ring connectors on a threaded lug post.



Besides what circuitry you are checking already, the next component that might be an issue is the front body control module. It is located in the passenger's foot well below the glove box on a LHD. This is the control unit for many items including both main/dip HLs. If the module is bad that could be your problem, or, it could be as simple as a bad/loose connector on the module. There are several connectors. Here is a pic of the FBCM:

 

Thanks for that info BWings! I'll check into this today

 

To help with a little deciphering:

C0xxxx - are components
X0xxxx - are connectors
S0xxxx - are splices
G0xxxx - are grounds.

In the first pic, C00106 through C00124 = the ABS unit.
C00387 through C00726 = the headlamp and its parts
C00589 = the purge valve, bank 2
C00570 = air flow meter bank 2

In the second pic:
C00370 = Front body control module

Hope that helps.

These IETIS layouts are incredibly complex and incredibly time consuming to review. Such a poor way of laying out the electrical system in documentation.

 

@cduluk1 did you ever resolve this issue? If yes, were you able to determine a root cause?