Hello, My name is Scott and I will gladly assist you with your vehicle concern.
As things go, when you turn on the lamps, the engine will idle up to take on the load of the alternator having to put out more to keep up with load demand. If this has happened recently, there is a good chance that either the battery is older or the alternator could be getting worn.As far as the ticking, the injectors will also have to pulse more, and will do so at a faster pace. Chances are, if these are original injectors, the are going to be worn a tad after 24 years of service.if there is no running problem and the vehicle is operating normally, I would say this would give you some piece of mind. If you want to pursue the concern, I would start with having the charging system checked and verify the battery and alternator are up to snuff.
If you were my client at the shop, I would do that as a courtesy, and send you on your way if they checked out until either the injector failed or there was an actual failure of an item.