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Most likely, the issues you describe are being caused by a bad ground connection. Starting with the headlight you previously repaired, check that the Brown wires in the harness have a good connection to ground (close to 0 Ohms resistance or less than 0.1 volts drop). Another possible place that's commmon for these vehicles to loose body ground is under the battery tray (see Gnd. 12 in attached graphic).
Please let me know if the information I've provided helps you solve your issue or if further assistance is needed.
Well, that's the thing; you need a multimeter to test electrical circuits, visual inspections alone are just not enough. I'll opt out and re-open your request to the field so others may chime in. Please don't reply until another expert responds or the site will revert your request back to me.