Welcome Earle. We small but tight over here. You should check the e39 FAQ . Are your elecrical issues in the truck? Some e36 owners have had issues with wiring and where it enters the rear of the car. I suggest starting with the FAQs however I'm sure others have had your problems.
Another idea , not to gross you out, but I have a good friend with a Honda Fit, they let the car sit for a few months... Rodents had destroyed the wiring under the hood by nibbling and urine. Long story short -3000 bucks worth of harness and labor (covered by insurance).
Hope thats not your issue.
All the best!