Check your plug to see if it matches the first one. Most of these were made to plug right in. There might have been some that were more universal that you spliced in too.
I sold a lot of these from junk yard cars/trucks but I'm not an expert on them.
Funny thing... when I was selling these on a regular basis, a guy from Japan bought most of them.
He must have had a huge collection of them just from what he bought from me.