Yes the dome light. Personally I would cancel the four new series plugs as well if possible. If you are going to spend more than a few dollars the upgrade is far better value.

I think your current system can be troubleshot and made workable until you get the newer plugs. They may or may not be a little harder to find.

I believe without being absolutly certain there is also a strip fuse on the firewall in the system you have. I have one car with your setup but have had no issues with the glow plug circuit so am unsure. Keep that in mind as well.

Your glow plug relay is above the floor pedals incidentally. Auto wreckers or some of the guys on site can save you decent dollars if you ever need one. I wish we had a pick and pull operation anywhere near me.