Yes

 

I bought 1 of these at an auction for $25 and love it but wouldnt pay $300 for it.
https://www.etrailer.com/Wiring/Hop...928.html?feed=npn&gclid=EAIaIQobChMIzLOq49m73wIVBAVpCh34oQ4CEAQYAiABEgKtVvD_BwE

 

We build trailer testers. I can post some pictures when I get back to the shop on Thursday

 

On Thursday....most places took Monday and Tuesday.

 

My onsite rrepair guy made his own

 

Bought one of these a few years ago.

https://ipatools.com/products/9101-ranger-mutt-trailer-light-tester.html

 

Cigarette plug to two prong? Is that to plug into the truck inverter?

 

With no snow, just take the week off no one will notice.

 

Any other leads?

Post some pics of the home made boxes

Our calendar year end last Saturday.....guess how many hours I clocked for the year.....?

 

I'll get you a picture tomorrow,
Has two boxes
Setup on an old dolly.
Each circuit is on a switch, each switch has a light in the box to confirm it's on. Connections are soldered to ensure a good connections. Has a 7 way round truck side, pretty sure there's an adapter for 6, and use an adapter for the 4 flat.
Access to the battery is important because you'll want to charge it?

 

Here are the photos of the tester we use ourselves, and the portable unit we make to sell

 

https://www.uniquetruck.com/category/868/trailer-testers

 

Bought one of these a few years ago.

https://ipatools.com/products/9101-ranger-mutt-trailer-light-tester.html

That thing is great, small, has its own battery.. Been using one of them for years.

 

I have many trailers I use for my business and recreation. A while back I bought a Trailer Tester from that tests both the lights and brakes...the tool is so convenient to use and has saved me a bunch of time. I got the model LT45. Here's a link to their site.
https://light-tester.com/