Truck and Trailer wiring tester

[Yoda]

With the recent posts on wiring between the truck and the trailer I went looking for testers for our 7 pin blade plugs. I found plenty of Truck testers like this, https://www.amazon.com/CURT-58270-Ve...%2C188&sr=8-10 But found nothing to check the trailer side - I.E. a male blade tester to plug into the trailer male plug.

I did find this round pin testers for commercial trucks https://www.amazon.com/CURT-58270-Ve...%2C188&sr=8-10

Not sure it the wiring is correct though. do commercial trucks use the samr configuration? Has anyone seen a tester that can plug into the trailer end? It would need to have the 7 blade connectors somewhere? I did fond a blade to round pin adapters https://www.amazon.com/MECMO-Round-B...1zcF9hdGY&th=1 and for the truck side https://www.amazon.com/MECMO-Connect...zcF9hdGY&psc=1

There is also thins but again round pin have no idea if it is RV. https://www.amazon.com/7-Way-Trailer...0O7S4J2Q&psc=1 I am looking for a flat (blade) pin version for RV's

Thoughts?

Keith

[Jlawles2]

I guess is someone were a bit creative they could add https://www.etrailer.com/Trailer-Wir...hoCESgQAvD_BwE to https://ipatools.com/product/super-r...railer-tester/ and test the trailer side.

found a cheaper version even though you would not want to save the money b/c the remote one is just cool. https://www.amazon.com/dp/B0120XZ234...NrPXRydWU&th=1

and i found this one https://ipatools.com/product/9101-ra...-light-tester/

[TribForce]

With the recent posts on wiring between the truck and the trailer I went looking for testers for our 7 pin blade plugs. I found plenty of Truck testers like this, https://www.amazon.com/CURT-58270-Ve...%2C188&sr=8-10 But found nothing to check the trailer side - I.E. a male blade tester to plug into the trailer male plug.

I did find this round pin testers for commercial trucks https://www.amazon.com/CURT-58270-Ve...%2C188&sr=8-10

Not sure it the wiring is correct though. do commercial trucks use the samr configuration? Has anyone seen a tester that can plug into the trailer end? It would need to have the 7 blade connectors somewhere? I did fond a blade to round pin adapters https://www.amazon.com/MECMO-Round-B...1zcF9hdGY&th=1 and for the truck side https://www.amazon.com/MECMO-Connect...zcF9hdGY&psc=1

There is also thins but again round pin have no idea if it is RV. https://www.amazon.com/7-Way-Trailer...0O7S4J2Q&psc=1 I am looking for a flat (blade) pin version for RV's

Thoughts?

Keith

Semi truck and RV trailer wiring is different. On the semi trailer the turn and brake signals are on different circuits. If one were to build a trailer side tester it would need a power supply and would be complex and expensive.

[Jlawles2]

Luckily the RV has its own power. Look at the last link in post 2, that is a RV blade tester.

[Country Campers]

I was thinking of building one of these last weekend. All one would need is a flasher, battery power and a few switches.

Brian

[Yoda]

I guess is someone were a bit creative they could add https://www.etrailer.com/Trailer-Wir...hoCESgQAvD_BwE to https://ipatools.com/product/super-r...railer-tester/ and test the trailer side.

found a cheaper version even though you would not want to save the money b/c the remote one is just cool. https://www.amazon.com/dp/B0120XZ234...NrPXRydWU&th=1

and i found this one https://ipatools.com/product/9101-ra...-light-tester/

Zoro has it cheaper https://www.zoro.com/innovative-prod...01/i/G5564916/ at 172 and the current 20% off coupons work. $145 with tax and 2% back with Capitol 1. Both Honey and Capital one coupon programs found good codes. It works with round pin plugs too as well as flay 4 wire plugs. the adapter is included. This would do the job for what I was thinking. Too bad it's so pricey Now Howard howson or Jim TucsonJim might find it handy. On edit Brian Country Campers already built for you

[Jlawles2]

Yoda Well Keith if you buy the Mutt tester and the Curt tester (https://elitetruck.com/products/5149...B9z0vsM5TxfSo4) you could rent them out for $20 a week plus shipping to fellow members and recoup some of the money....

I guess if you wanted to save some money you could get the IPA version for about 1/2 the price, but you loose the rest of the pin testing. https://ipatools.com/product/9107a-e...rcuit-testing/

This be one expensive pelican case: https://ipatools.com/product/tactica...e-force-meter/

[Jkwilson]

Trailer light testers are simple to make. You need a truck-side 7-pin and 6 alligator clips. Wire long enough to reach a battery. Wiring should be obvious. Connect the ground to the battery negative, then the appropriate wire for the circuit you want to test to the battery positive.

You can test brakes and backup lights in addition to the tail and stop/turn lights. If you want to make it idiot-resistant, add a fuse to the ground lead. Cheap and easy to make.

[Dave27]

I have just used a multimeter. Alligator clip to the negative pin, then touch the positive to each pin you want to test. It’s very easy and I don't need to buy or build anything.
Dave

[Jkwilson]

I have just used a multimeter. Alligator clip to the negative pin, then touch the positive to each pin you want to test. It’s very easy and I don't need to buy or build anything.
Dave

How exactly would that test a trailer?

[Jlawles2]

He is suggesting using the alligator clip to stimulate the individual circuits.

Reality is that you could use a truck side plug with the alligator clip on the 12V+ terminal and stimulate all of the individual circuits by moving to each one skipping the reverse lights unless equipped and the ground pin.

[Jkwilson]

He is suggesting using the alligator clip to stimulate the individual circuits.

Reality is that you could use a truck side plug with the alligator clip on the 12V+ terminal and stimulate all of the individual circuits by moving to each one skipping the reverse lights unless equipped and the ground pin.

“Alligator clip to the negative pin” would accomplish nothing in that scenario.

[Jlawles2]

“Alligator clip to the negative pin” would accomplish nothing in that scenario.

LIGHT SHOW. Let out all the angry pixies.

I guess a creative person could make a simple plug setup with a 2 pole flasher and several flip switches for each circuit. By the time it's all said and done you are probably in for $50 or so without a battery.

[TribForce]

I have just used a multimeter. Alligator clip to the negative pin, then touch the positive to each pin you want to test. It’s very easy and I don't need to buy or build anything.
Dave

As Dave suggests, with the meter set to ohms this will test the continuity of each circuit. If you want to see if all the lights light up you could use a power probe hooked to the battery. Here is the cheapest one on amazon. https://a.co/d/cJWJhBb I recommend an actual Power Probe brand. This tool will energize each circuit so you can check all the lights.

[RPAspey]

LIGHT SHOW. Let out all the angry pixies.

I guess a creative person could make a simple plug setup with a 2 pole flasher and several flip switches for each circuit. By the time it's all said and done you are probably in for $50 or so without a battery.

I made a test box to check the trailer with some switches, a flasher and test plugs for checking brake load. no battery is needed as on the trailer 12v is already on the 7 pin. I'll try to dig up a picture of it.

BTW, I use a DC ammeter across the test plugs to apply 12v to the brakes. I can then check the current that all 4 magnets draw in total. If one is bad, the load drops by 25%. For the life of me, I can't remember what full load value is right now, but I have it written down.