Comments on: Mystery Trailer Adapter With Beep Tester

By: Nate Bezanson

Nate Bezanson — Sat, 14 Apr 2007 21:57:08 +0000

So with the four-wire tester, you’d either need an extension cable, a mirror, or a helper. Not bad, though.

When I took a trailer back to NationsRent to have the [poorly maintained and disintegrating] wiring serviced, the mechanic brought out a fascinating homemade tool: A small toolbox bristling with switches and indicators, with pigtails of trailer plugs extending from both sides. Plugged into the vehicle, it emulated a trailer and would show bright colored lights for each signal. Plugged into a trailer, its internal battery could drive any trailer lighting circuit at the flip of a switch.

The only way to improve it would be a remote key fob to control it, so you could plug the box in at the tongue, then walk around behind the trailer and push buttons. Hmm.

Okay, after a little Google work, it appears that TrailerTester.com already makes a number of remote-controlled testers just like that, for large semi trailers and RVs. Obviously priced for professional use, but that’s cool. We mere mortals will stick with the twenty-buck version, methinks!

By: Roscoe

Roscoe — Sat, 14 Apr 2007 17:50:55 +0000

It only works for the flat 4-blade plugs, but I stumbled upon this cheap tester from U-haul a couple weeks ago an am impressed. It does just what it says it does. It would probably work with an adapter as well to test other plugs.

http://store.uhaul.com/product_detail.aspx?id=4821

By: Myself

Myself — Sat, 14 Apr 2007 02:51:07 +0000

I’m willing to bet the “do some stuff” involves a set sequence like: Tap the brakes twice, then try the left turn signal, tap the brakes again, try the right turn signal, press and hold the brakes while hitting reverse briefly, then shift back into park, release the brake, and go look at the tester.

It’d be easy to watch for sequences of signals. If a signal doesn’t arrive, or arrives out of order, throw an error so the operator can go get another human to help diagnose the problem.

It’d be worth checking out if it also worked on 4-pin plugs. That would require an internal battery though, and might bump the price a bit.