So I googled ‘7way trailer tester’ and they were all very expensive.

What do I do?  I made my own.

30 minutes and less than $20 + some stuff I had in my shop.

And it works.

Here’s what I did.

I found a small project box in my shop (it happened to be the right size: about 7″x4″x2″).. and I had an idea.  I also found 5 momentary switches, one on/off switch, and a female 12v port that I already had, and a pile of wire

So off to AutoZone I go.  I picked up a $10 female 7way connector.

30 minutes of wiring later, and I had a valid 7way tester.

I didn’t make a wiring diagram, but basically 1 wire (black) on the 7way is ground, and the other 6 are all 12v positive, and each of those go through a switch (the aux one goes to on/off, and the other 5 go to momentary switches) and then I just crimped all the right ones together.

See the images above, and the video below.