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Features:
Note: On trailers with LED lights, amperage will not display.
California residents: click here
Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.
Today we're going to be taking a look at the Hopkins Tow Doctor trailer end test unit, part number HM50928. This Hopkins Tow Doctor allows one person to check their trailer wiring and make sure all their functions are working correctly. It's going to come with adapters to work with your seven-way, your four-pole flat, and your six round. It's got your right turn brake, your left turn brake, your tail lights, your backup light, your brakes, and even auxiliary power. If the green light appears, the circuit checks out okay. There are no missed wire connections, burnt out lamps, or trailer shorts to the ground. The LED screen shows your amperage, but it'll also show you your overload, a short circuit, and your low battery.
The included terminal clips allow you to connect it to a power source such as a car battery, and the cable is about eight foot long and is fuse protected. The Tow Doctor module itself features rubber bumpers around the ends here so it can withstand a beating. The whole Tow Doctor system is great for someone who has a lot of trailers that are constantly on the road to where they need to check them quick and easy. Now that we've got all the features, I'll go ahead and show you how to use it. I'm right here next to my trailer, let's go ahead and open up our case. Our trailer here has two different connections, because its owner tows with two different vehicles.
We've got a seven-way here, and then we've got a four-pole flat connection. We could look to our adapters in our case here, we can test either the seven-way or the four-pole, but since our Tow Doctor will test our brakes too, let's go ahead and test the seven-way. After choosing our adapter, we can go ahead and plug it in to our Tow Doctor. That's just going to be at the top here. What we'll need to do is line up the grooves, or the teeth with these slots on top, and then screw it in place. Just like that.
From there we can go ahead and plug in our seven-way. The clip here is going to be for our ground, but we won't be needing it because our trailer wiring is already grounded. But if we're to need it, we would just attach it to a non-painted surface on to our trailer. Now let's hook it up to a power supply. We've got the two alligator clips here, got our positive and negative, so we can hook this up to a 12-volt or greater power supply. You can use a car battery if you'd like.
We're going to be using a jump box, so our red is positive, goes to the red connection, and our black to the black connection. That's going to be negative. Now we can run through the functions. I'll press the right brake button and without even checking my light, I know that it's wired correctly and that it's working correctly. For one, it's green, and it's showing the correct amps. It's not showing an OL for overload, or SC for short circuit or LB for a low battery. Now I can just run through and check them all. As you can see with the right brake engaged, the right brake light is on. Then we could do left, that comes on, and then we click on tail light, the whole rear of the trailer lights up. If all of your functions are working properly and you don't need to repair anything, you're all set. That's going to complete our look at the Hopkins Tow Doctor trailer end test unit, part number HM50928.
Average Customer Rating: 4.8 out of 5 stars (29 Customer Reviews)
This is an essential tool for anyone working with large numbers of trailers. As a trailer dealer, we often encounter situations where we need to test trailer lights, or demonstrate the lights are working correctly. This tool has saved us countless headaches. We highly recommend!
I ordered this one an the truck one this one is missing the 7 way plug So just make sure you get your parts
Easy to use. All the adapters included.
Though I don't do a whole lot of trailer work, every time that I've hooked this up to test a trailer's wiring, it worked very well. I never had it malfunction. The fact that it gives the amperage draw of each circuit and it's energized is very useful for diagnosis. Seems solidly made. I recommend this tester.
Excellent product!! I own a new vehicle and had problems with the 7 pin trailer wiring from the vehicle. The car manufacturer blamed my trailer for the problems. After purchasing this machine and running thru the series of test's I was able to prove that the car dealer was incorrect in the diagnosis (which i was suspicious of to begin with) and that it was a bad electrical system in the vehicle... Not my trailer. Thank you etrailer for the excellent product, insanely fast shipping. The you tube video's of this product showing all the in's and out of how it works and it's effective use were also greatly appreciated. I am Canadian, and will be purchasing more great priced, products from your site. Thank you very much!
Item is nice to have on hand for a single person to check trailers as they come in, and have them ready to go back out. Fairly easy to use. a magnet on the back would be ideal to hold to trailer tongue while performing tests.
I love it. No more hooking up truck to check wiring on trailers. One man job!!!!!
Bought this item to check trailers and the vehicle tester too. Both work great and save me tons of time checking trailer circuits on our fleet.
Great unit. Having. 12v battery included would make it a complete package, but it's not difficult to source one either.
It seemed pricy but my son and I have a lot of trailers to deal with so figured it was worth it. Tested one trailer...worked well. Agree with other reviewer.....nice if it had a battery.
Excellent investment, has save money and time. Recommend to any shop of trailer owners. Hassle free, and portable.
What a nice tool....just what I was hoping for. I tried it out it worked great. It is built well, with its own nice case and is simple to use.........
Lynn
2/22/2020
Still like the product, the only improvement would be to have vehicle specific connectors so that you could have a no wire cut install..... I have had some wire breakages on the vehicle side with the small led wiring of the pickup, If I had had a spilt connector with the vehicle specific connectors it would eliminate this problem
Lynn
2/23/2020
Still liking it, really good tool
The service was superb I did an exchange and the folks there made it so easy and I received the correct one (i miss ordered ) very promptly I will continue to do business with etrailer
Thank You
Kevin D
Has worked well in our production setti ng.
E trailer is great got my order very quickly and the tow doc makes my life doing inspections a lot easier.
Having had the product for a year now it has proven to be very useful. We can do diagnostics with out having the trucks hooked up! Great product!
Improved design from the original design product, easy to use, excellent product
Mark
3/20/2022
I have used this tool many many times to diagnose trailer lights. It is fantastic.
Product was as described and worked as it was designed..
Product received as ordered and very timely. Great service, would highly recommend.
just received my package. Excellent communication throughout the transaction. Item is as described. Will definitely do business again.
Works very good
great product. appreciate the discount compared to direct purchase.
great packaging and fast shipment.
easy to order.
So far so good. Just received the package today.
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11/21/2022
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