Repairing A Wireless Towing Light Kit

[ButchW]

I bought a cheap Harbor Freight (Yea, I know ) Wireless Towing light kit to tow my 1986 Suzuki Samurai behind my motor home...... I'm trying to keep the Samurai as stock as possible, so went the easy way with no drilling or cutting... Anyway, after about 6 uses one of the lights stopped working... Past warranty, but called them any way... There reply was to toss them in a trash can and buy new ones... Nope, they aren't getting anymore of my money for lights... The units are sealed, but I got the broken one apart and they have a 3-18650, 2000mAh, 3.7V battery pack in them... It is reading 4.1 V, which I assume is ok... I'm not good with electronics, but figured I could replace the battery pack... But that seems fine correct?... I hate to just chuck $130 out the window as they are like new, seem pretty well made and worked very good, until they didn't... Anybody ever have any dealings with these things?
Thanks, Butch

 

[Lark Hunter]

I haven't been into one of these systems at all, but your battery voltage looks right square in the normal range, so you're good there.

I'm guessing the problem lies in the receiver unit in the dead unit... not picking up signals from the modulator that's commanding it from the tow vehicle. Have you double checked to make sure one of the connections between the motorhome and the modulator hasn't been compromised?

And a stock '86 Samurai? Dig it!

 

[ButchW]

Thanks...Yea, it's completely original except for paint, rims and one size larger tires,...
With or with out the sending unit plugged in, it does the same thing... The unit is supposed to have the indicator lights come and stay on when you turn each light on... One unit does this and works fine, but the other just keeps the indicator lite flashing on and off after turned on, and doesn't work... So I believe the sending unit and connection to the motor home is fine... It seems to be in the electronics of one of the lights... This is the set I have...

Magnetic LED Wireless Towing Light Kit

Amazing deals on this Wireless Led Towing Light Kit at Harbor Freight. Quality tools & low prices.

www.harborfreight.com

Thank you for the help...
Butch

 

[bshanahan14rulz]

https://manuals.harborfreight.com/manuals/58000-58999/58469-193175439819.pdf

This was mainly only useful for a laugh. I liked the disassembly instructions. "1. Using a hammer, ..." sounds like a good start!

Got any pics of the circuit board? I doubt there's anything visually wrong, nothing that I would recognize, but maybe someone else on here might be able to shed some light on possible issues.

 

[turbodog]

good luck

 

[ButchW]

Thanks guys…. I'm going a different way on tow lighting for the Samurai…But still would like to repair them, if possible… I'll get some pics of the board tomorrow and post them here… Hopefully someone can figure it out… I hate to just throw them in the trash… I know enough people that tow, that they would come in handy...
Buch

 

[ButchW]

Haven't taken pics of the board yet, but here's the Samurai...


Butch

 

[ButchW]

Ok... Not great pics, but this is the circuit board...

 

[ButchW]

If anyone here can see anything wrong, please let me know... I see nothing obvious, but if a component was bad, I'd never know... I was a construction electrician for 43 years (+2yrs in the military), but don't know squat about electronics... ..
Butch

 

[Lark Hunter]

Thanks...Yea, it's completely original except for paint, rims and one size larger tires,...
With or with out the sending unit plugged in, it does the same thing... The unit is supposed to have the indicator lights come and stay on when you turn each light on... One unit does this and works fine, but the other just keeps the indicator lite flashing on and off after turned on, and doesn't work... So I believe the sending unit and connection to the motor home is fine... It seems to be in the electronics of one of the lights... This is the set I have...

Magnetic LED Wireless Towing Light Kit

Amazing deals on this Wireless Led Towing Light Kit at Harbor Freight. Quality tools & low prices.

www.harborfreight.com

Thank you for the help...
Butch

Sorry for the later than late reply. With your last description of the issue, it sounds more like something is morked up with the electronics inside the one light, as it malfunctions before even receiving information from the tow vehicle transmitter. I'm a reasonably seasoned electrician as well (commercial, residential, and automotive), though I've only gotten far enough into electronics to identify and test discreet components. I see four IC's (marked with a "U" on the board), and I'm betting there's a problem in one of those... guessing U3 or U4?

I scanned a few reviews, and see a couple complaints similar to yours, though most are complaining about the gimpy magnets... and the manufacturer doesn't even sound too sure about their holding force. On one hand, I'm not super surprised to see janky stuff from Harbor Freight, but the other is taken aback that they're charging $130-140 for these and telling you to trash 'em like a $3.99 flashlight when they crap out after a couple of uses.

Two thumbs up for the Samurai, though! Factory wheels, factory ride height, and that color!

 

[turbodog]

Get yourself a magnifying glass and inspect the circuit traces and solder joints. You might find a crack.

I did this with my sport car... headlights got wonky. The high beam relay had 2 of the 4 solder joints that cracked. It was a known issue, but still...

 

[ButchW]

Sorry for the later than late reply. With your last description of the issue, it sounds more like something is morked up with the electronics inside the one light, as it malfunctions before even receiving information from the tow vehicle transmitter. I'm a reasonably seasoned electrician as well (commercial, residential, and automotive), though I've only gotten far enough into electronics to identify and test discreet components. I see four IC's (marked with a "U" on the board), and I'm betting there's a problem in one of those... guessing U3 or U4?

I scanned a few reviews, and see a couple complaints similar to yours, though most are complaining about the gimpy magnets... and the manufacturer doesn't even sound too sure about their holding force. On one hand, I'm not super surprised to see janky stuff from Harbor Freight, but the other is taken aback that they're charging $130-140 for these and telling you to trash 'em like a $3.99 flashlight when they crap out after a couple of uses.

Two thumbs up for the Samurai, though! Factory wheels, factory ride height, and that color!

Thanks for the reply and thumbs up... I should have known better than spend that kinda $ for Harbor Freight stuff.. Some of their things are OK'ish... They do seem pretty well made and worked very well the few time I did use them... The magnets weren't bad, but I tied them off anyway, and I didn't trust the sending unit in the RV's receptacle (No real locking mechanism)...
The Samurai is a ton of fun, and I get the old thumbs up or comments everywhere I drive it... It's pretty much stock except for the paint and tires.. The color is kinda goofy (I bought it that way), but it definitely gets the looks, and is part of its charm.. Thanks again...

Get yourself a magnifying glass and inspect the circuit traces and solder joints. You might find a crack.

I did this with my sport car... headlights got wonky. The high beam relay had 2 of the 4 solder joints that cracked. It was a known issue, but still...

I took a pretty good look at the very fine traces and solder joint, but I'll have a closer look with a magnifying glass... I've wired into the Samurai's existing lights for towing, so I really don't have to get this fixed, but it just bothers me to just toss it... If I can fix it cheaply, I will, for me or others to use...
Thank you for the suggestion....
Butch

 

[LEDphile]

Given the almost complete lack of protection circuitry on that board and the direct connection from the control and power ICs to the outside world (and automotive electrical systems aren't known for being benign electrical environments), I suspect that at least one of the ICs has been fried. Whether or not that's an easy/cheap repair depends on if the IC is readily available, and your skill with SMT rework.

 

[turbodog]

Maybe the lights are doing the correct thing and the problem lies with the brain unit sensing the wrong info from the tow plug. Check for continuity from the plug into the unit.

 

[turbodog]

Given the almost complete lack of protection circuitry on that board ...

From harbor freight? Hush your mouth!

 

[ButchW]

Whether or not that's an easy/cheap repair depends on your skill with SMT rework.

Well, there goes this project. ....
Butch

 

[alpg88]

this thread may get more qualified responses in home made and modified lights, there is where people who make/design circuits frequent more than automotive section, this is not about choosing a right light for a car anyway, it is about fixing an electronic circuit

 

[bshanahan14rulz]

Often, ICs have the + and ground pins in the same spot, almost like a standard. With a multimeter, you could make sure that the ICs are getting voltage on those pins. Look up what pins are usually Vdd and ground on common ICs if you can't read the writing on U3 and U4, and see if you can see a measurable voltage being supplied to the chips when the device is on.

Maybe the bad light just continuously turns on its indicators, lacks input power, and shuts off from low power, before starting the cycle over again. (I've seen a few devices which would just keep turning off and on again due to a failing power supply not supplying enough power). These are LEDs, so I think a battery would need to be VERY unhealthy for this little device to sag the voltage so low that it shuts down. But, perhaps measure the voltage of teh battery when the device is off and compare it to when the device is on. If the battery is shot, you ought to see the battery voltage sag quite a bit as it struggles to deliver current. You could then confirm by temporarily replacing the battery.

Lastly, an observation with no thought: it seems strange to me that there is an oscillator on its own special board. Wonder if that is how they "customize" sets to keep one set from accidentally controlling a nearby identical set... And if that getting loose may cause it to think it is not near its transmitter.

 

[ButchW]

Thanks for the advice guys… I'm a bit tied up right now, but I'll do some more research on it as soon as I can. Thanks again.
Butch