Trailer Light Tester, home brew

[malykaii]

So I'll be covering for the tractor and trailer guy for a few weeks and lack a Class A license. Made this to get by.

It hooks up to the shop car's battery and sends power to all lights. 25amp inline fuse. Flasher makes both the brake and turns flash.

Any concerns or improvements to my new toy? Co worker thinks it's a hack job.

 

[gdocktor3]

I don't understand. What are you trying to do? Just test lights on a trailer?

 

[malykaii]

^Indeed. Just want to know which light is out when a driver writes up "market light out"

 

[Rookie2]

I just turn the lights on !

 

[dadsEH]

Lol......well he does have a point. How do you turn on lights without hooking up to a vehicle? I reckon its a time saver.

 

[gdocktor3]

Can't you just use a little cart or hand truck with a battery instead of using the shop vehicle and going through all the nonsense of opening the hood etc?

 

[malykaii]

I can't hook up the trailer to a tractor because I don't have a license to operate them.

Hence I figure I can just clamp my dohicky to any power source, be it the shop car, the jumper cart, or any car batteries we have lying around.

 

[malykaii]

Its versatile, so I plan on using it with the booster cart for nearby trailers.

You bringing this up makes me realise I should ad some sort of hook or clip to make it stay on the booster cart.

Thanks!!

 

[Outlander]

Mine is just as much a hack job, only uglier. I use a surplus 12V power supply with alligator clips small enough that they attach to the trailer plug pins.

Somewhere on the GJ there was a posting (no idea how to search it) from a guy who had made a 12v or trailer service cart which I thought was neat even as it even had wire storage built in.

 

[Rookie2]

I can't hook up the trailer to a tractor because I don't have a license to operate them.

Hence I figure I can just clamp my dohicky to any power source, be it the shop car, the jumper cart, or any car batteries we have lying around.

If your in a parking lot or on company property why would you need a license ?
Where is your wiring harness ?

 

[BlackLS2]

He came up with a tool that worked for him...and he was cool enough to share it with us. I say BRAVO!

Love the flasher!

 

[ibedayank]

If your in a parking lot or on company property why would you need a license ?
Where is your wiring harness ?

insurance!!!!

 

[zendriver]

I have a CDLA and I have never heard of a license being required to move a tractor-trailer on private property. It's not, where I work.

Sure you could do some damage but you're not going to do that much driving at 5 miles an hour.


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[wolf_from_wv]

I made one for 4 wire trailers... It can be connected to the vehicle to see if that part is working with a 12V buzzer, or it could be hooked up to a jump pack and be used to test the trailer by itself.

 

[Outlander]

I made one for 4 wire trailers... It can be connected to the vehicle to see if that part is working with a 12V buzzer, or it could be hooked up to a jump pack and be used to test the trailer by itself.

Oh my! That looks cool. Any chance of seeing the inside or getting a wiring diagram? I enjoy small electronics projects like this.

 

[Outlander]

Mine is just as much a hack job, only uglier.

To the OP, that was a compliment BTW. I just re-read my note and it didn't sound like one

 

[FigureItOut]

I've seen those things for sale, with an integrated battery and in a nice package, for way more than you'd think. So there is obviously some market for them. I bet you'll end up improving your system there. I've made similar stuff.

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[maxpower_hd]

We have one that is rigged up an a two wheel dolly with a battery. I do move trucks around from time to time but usually I am using a yard horse and ours does not have the electrical connections. But you can lift the trailer and move it without moving the landing gear so it is a plus. We also sometimes go around to the trailers without a tractor. Plus having a known good tester eliminates having to determine if the issue is with the truck or the pigtail from the truck during a PM. Saves time.

 

[malykaii]

I have a CDLA and I have never heard of a license being required to move a tractor-trailer on private property. It's not, where I work.

Sure you could do some damage but you're not going to do that much driving at 5 miles an hour.


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Its not a mom and pop operation. You need to be certified just to work the a/c machine and need to take an internal course to operate a forklift.

I've seen those things for sale, with an integrated battery and in a nice package, for way more than you'd think.

I was going to ask them to buy one, but at $300 dollars just for a few weeks is pointless

 

[malykaii]

To the OP, that was a compliment BTW. I just re-read my note and it didn't sound like one

Please tell you have a pic of this thing!

I know what you meant.

 

[maxpower_hd]

Its not a mom and pop operation. You need to be certified just to work the a/c machine and need to take an internal course to operate a forklift.




I was going to ask them to buy one, but at $300 dollars just for a few weeks is pointless

I don't need a license at my work either and it is a large worldwide company. The largest from what I am told. But I am a contractor with my own liability insurance so they don't really care about me one way or the other. Also they are a Union company and have had several guys who have lost their licenses for DUI, for example, who have stayed working the dock and jockeying trailers around the yard, fueling trucks etc. So some places do allow it.

I believe this company is self insured and so was the last one I worked at so maybe that is the difference.

 

[Wanna Ride]

Damn, some of you guys take stuff too literal. The point the OP was making is, that if for whatever reason a tractor isn't available, he can just hook up the adapter he built, and can move forward testing lights. Take your head out of the sand and realize that every situation, every yard, every location is not identical to yours.

Good job OP, some of us were keeping up with you. That looks like a simple, but handy tool.

 

[Outlander]

Since I am puppy watching (new French Bulldog) and drinking coffee on vacation, I have too much time on my hands so I am scouring the interwebs for new projects. This trailer wire tester peaked my interest. Yes, lots's of $300-400 options out there, so the home-brew solution for pennies sounds great.

I found this one interesting for people with shops, not quite so portable

http://www.protatch.com/trailertester.htm

Since I have a spare ATV battery, does not hold charge in winter like it should, I could even consider one that fits in an ammo can or plastic tool box. I probably have everything I need, including the beer.

 

[zendriver]

Its not a mom and pop operation. You need to be certified just to work the a/c machine and need to take an internal course to operate a forklift.

Ok, so your company is bigger than my company, but your truck mechanics don't require any certification?


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[malykaii]

Ok, so your company is bigger than my company, but your truck mechanics don't require any certification?


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Oh theres plenty of certifications. I have them to work on the step van delivery trucks as that's what I do. However the tractor guy took all his vacation weeks in a row so I'm covering.

All they want is for me to fix the essentials... Tires, body damage, and lights. All big stuff Will be fixed when he gets back.

 

[malykaii]

Since Yes, lots's of $300-400 options out there, so the home-brew solution for pennies sounds great.

Since I have a spare ATV battery, does not hold charge in winter like it should, I could even consider one that fits in an ammo can or plastic tool box. I probably have everything I need, including the beer.

Yeah, for a plastic box, small battery, and a handful of switches and relays they sure are expensive. The ingredients can't cost more than $30 So why such a mark up. I figure $100 is fair, not $300.

 

[Rookie2]

Oh theres plenty of certifications. I have them to work on the step van delivery trucks as that's what I do. However the tractor guy took all his vacation weeks in a row so I'm covering.

All they want is for me to fix the essentials... Tires, body damage, and lights. All big stuff Will be fixed when he gets back.

Their lucky to have you ! I hope they appreciate your effort.

 

[maxpower_hd]

Ok, so your company is bigger than my company, but your truck mechanics don't require any certification?


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The need certifications for certain things but not a Class A license to drive. Only one of the three mechanics that I work with have one and the one that does only has it because he used to drive on the road. It happens all the time.

 

[Wanna Ride]

Oh theres plenty of certifications. I have them to work on the step van delivery trucks as that's what I do. However the tractor guy took all his vacation weeks in a row so I'm covering.

All they want is for me to fix the essentials... Tires, body damage, and lights. All big stuff Will be fixed when he gets back.

You don't have to explain this to these asshats. You were challenged to find an easy solution to the task at hand, and you did a fine job addressing that. None of these guys on here sign your paycheck, so you owe them no justification. Press on, good man!

 

[Outlander]

@Wanna Ride I was hoping for some discussion on the alternative solutions for home grown testers, but we seem to have been lead down another path.

 

[Wanna Ride]

@Wanna Ride I was hoping for some discussion on the alternative solutions for home grown testers, but we seem to have been lead down another path.

Not by my doing. There's several members in here arguing with the OP about why he does, or doesn't need a CDL. Personally, I like the simplicity, effectiveness and how compact the test-rig he came up with, and if I still had a need for one, that's the one I'd replicate.

 

[larry_g]

. Flasher makes both the brake and turns flash.

Any concerns or improvements to my new toy? Co worker thinks it's a hack job.

I'm not up on trailer wiring so I have to ask, are any of the lights dual use where you could confuse the brake and the turn functions? Should you have a switch to select one or the other?

On edit, I went and looked it up and see the flashers are separate from the brake. The only problem you may create with both connected to the flasher is if you have a short it may be a bit more difficult to trace. If you have free access to switches then you could add in a few switches, one for each circuit, to isolate them individually if fuse blowing is a problem. If your going to be tracing shorts then a circuit breaker might be better than a fuse.

Other wise it looks great to me and should get the job done.

lg
no neat sig line

 

[Outlander]

Not by my doing.

Agreed!

If you have free access to switches then you could add in a few switches, one for each circuit, to isolate them individually if fuse blowing is a problem. If your going to be tracing shorts then a circuit breaker might be better than a fuse.

Other wise it looks great to me and should get the job done.

Over my gallon of coffee this morning, the ones I looked at had switches. Some even remote control switches so you could stand at the back and cycle through them all!

 

[FigureItOut]

Agreed!



Over my gallon of coffee this morning, the ones I looked at had switches. Some even remote control switches so you could stand at the back and cycle through them all!

It'd be easy to add remote switches for less than $30. This is making me want to make one.
OP, you can get a "project box" at radio shack to contain everything, then flush mount your vehicle side connector in the box. Throw a little $25 SLA battery in there with a size M barrel power connector for charging, and you've got yourself decent looking, self contained little unit.

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[Ign]

I think it's cool and have been meaning to build a 7 pin tester forever. I wonder if I could power it w a holster from M12 heated gear? Don't see why not.

What could you use to dial brake power? A rheostat? I guess just off/on would work though. Might be too much for an M12 battery however.

 

[firebox40dash5]

It'd be easy to add remote switches for less than $30. This is making me want to make one.
OP, you can get a "project box" at radio shack to contain everything, then flush mount your vehicle side connector in the box. Throw a little $25 SLA battery in there with a size M barrel power connector for charging, and you've got yourself decent looking, self contained little unit.

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One of the popular shop versions (the name escapes me) is built into a plastic ammo can. I was going to jack their idea and build my own, but I left the shop before I motivated myself to do it. Mostly because I couldn't find a cheap enough rotary switch like they used to separately power different functions. I'd probably grab some variety of lithium jump pack to power it these days, not much more than an M12 battery and shouldn't have to worry about drawing too much and hurting it.

As for usefulness... I think they're much better than a truck to test with. For one, you don't have to worry about whether the truck has a wiring issue too, or blowing a fuse in it. Sure you can test the truck as well to track down an issue, but I can also test a trailer with a Powerprobe, this is more convenient. Also means you don't have to go moving trucks around, and you can test a trailer parked in an inaccessible spot, too. I usually stuck them in the back corner of the shop, and getting a truck close enough blocked a lift and might mean moving a couple vehicles out of the way.

 

[Outlander]

Question for the heavier equipment guys. Are the big trailers wired like my 8 foot utility trailer? Besides being more robust etc.

 

[Wanna Ride]

One of the popular shop versions (the name escapes me) is built into a plastic ammo can. Mostly because I couldn't find a cheap enough rotary switch like they used to separately power different functions.
As for usefulness... I think they're much better than a truck to test with. For one, you don't have to worry about whether the truck has a wiring issue too, or blowing a fuse in it.

The Harbor Freight plastic ammo boxes are $4.99 with the coupon. For the dimmer switch, you could source one from a salvage yard, out of just about any car/truck? What makes this test rig more attractive, is that you don't need to jack around with a tractor/cab in tight, confined spaces. This style test-rig would definitely be much more efficient and easy.

Question for the heavier equipment guys. Are the big trailers wired like my 8 foot utility trailer? Besides being more robust etc.

Pretty much. They usually have the large, round connector. I know some smaller trailers can have either or. When I built my utility trailer, I purposefully wired it for the round, 7-pin harness. Basically, because it too is just more robust. Does your utility trailer have the straight, 4-pin connector?

 

[malykaii]

I'm not up on trailer wiring so I have to ask, are any of the lights dual use where you could confuse the brake and the turn functions? Should you have a switch to select one or the other?

On edit, I went and looked it up and see the flashers are separate from the brake. The only problem you may create with both connected to the flasher is if you have a short it may be a bit more difficult to trace. If you have free access to switches then you could add in a few switches, one for each circuit, to isolate them individually if fuse blowing is a problem. If your going to be tracing shorts then a circuit breaker might be better than a fuse.

Other wise it looks great to me and should get the job done.

lg
no neat sig line

Thanks for pointing out some shortcoming s.

1)There are four red "dual filament" lights in the rear. All four light on low when markers are on. Top two highs are brake, lower two are turns. So yes, confusing. I just realized I have power to both high and low brake lights, hence won't know if the low works. I'm thinking add a second Flasher to cycle the brake and turns separately. Thanks!!!!

2) Circuit breaker sounds good! I'll swap it out. Any idea what amp size?

3) yeah, this thing is only good for the usual smashed light or bad ground. Kind of useless for any real diagnostics.

3) we have some 7 way plugs with built in circuit breakers on each pin. Considered using one on a plastic box along with 7 switches. (aka real diagnostics) However we have a "no homemade tools" policy. Any bigger than it is I won't be able to hide it lolz!

 

[Outlander]

Pretty much. They usually have the large, round connector. I know some smaller trailers can have either or. When I built my utility trailer, I purposefully wired it for the round, 7-pin harness. Basically, because it too is just more robust. Does your utility trailer have the straight, 4-pin connector?

Yes it does, they all have had flat connectors and I am on my 5th trailer of some nature or another. Pain to keep clean, especially with our winters. I am constantly spraying them with contact cleaner and re-applying di-electric grease.

Thanks for pointing out some shortcoming s.

At the office I would tell my team we have an 'opportunity to excel' You are in your continuous improvement cycle!