RV Surplus 
 Amazon's RV Store 

Notice: This page may contain advertisements. Click on the disclaimer for details.

Replacing the Leaking Tail Lights.



Last fall, I attempted to replace one of the light bulbs in my tail lights. When I opened the light bezel, it was like Niagara Falls, as water literally poured out of the fixture. Bad news. So that event turned into a major repair job, and I waterproofed the area behind the tail lights with epoxy so that if it leaked again, at least it would not do any damage to the coach.

I also put new gaskets on the coach and did everything I could to ensure the lights would not leak. You can view that repair here: Repairing Leaking Tail Lights.


Unfortunately, when I inspected the tail lights during this spring's commissioning, I found yet again, water in behind the tail lights, so I was not successful in correcting the problem.

My first thoughts all along were that the lights (Command Electronics 003-30) are a bad design, which is why they leak. Also, the gasket is made of foam rubber and it crushes under compression between the light bezels and rear wall of the coach.

The main problem as I see it is you have to completely remove the lights to replace the bulbs, so you cannot seal the lights to the coach, but must rely on a sub-standard gasket to keep the lights waterproof.




I suppose I could have cut out new neoprene gaskets and that might have solved the problem, but the better approach is to just replace the lights. I did some searching on the internet and other resources, and I found an almost exact replacement; Bargman 34-84-009 (84 series lights). The original Command Electronics lights retail for about $27, while the Bargman versions are around $40. So for $13 per light, I have had to go through a whole lot of frustration.


And I don't think my case is isolated. I personally know of 5 other people that have discovered leaks in these lights (and it probably would be more, but most people don't check such things until the rear of their coach falls off).

Since these lights are one of the more popular lights used on many motorhomes, and are found on certain models manufacturered by Thor, Coachmen, Forest River, and Winnebago, there is potentially many motorhomes out there with water damaged motorhomes.


If you have such lights on your motorhome, I highly encourage you to check them.

The reason the Bargman lights are superior in my view is the bezel surrond can be permanently attached to the coach with sealant as access to the lights themselves are via the three lenses. While the lenses themselved do not have any gaskets, there is a channel wherein water is kept out of the innards. In the worst case scenario though, you can probably use an o-ring making kit to make o-ring gaskets under the lenses.

Replacing the lights were not very difficult as the new lights were within a 1/16 or so in width and height. The depth is about the same also. However, the backside protrusion is a bit taller, so I had to square off the cut-outs and enlarge the height about 1". I used a Porter-Cable multi-tool for this as well as a router. I would highly recommend using at least a multi-tool for cutting the coach's end wall as you can easily control the cut for some degree of precision.


Cut out guide.


For my particular coach, this is the cut-pattern. I had to shave up to 3/4 or so from the top, and square off the corners to ensure adequate clearance for the new lights. Of course, it should go without saying that it's better to make a narrower cut, then go wider if needed... and above all:


"Think twice, cut once".


When cutting, you cannot center the cut top and bottom as there is a metal channel that contains the wiring; I do suppose of course you could cut the top of the channel off. But there is no reason to make things more complex as even shaving the entire amount off the top still leaves ample space for the light to overlay the cut out.

As well, if you lowered the lights, you would have to relocate the license plate holder, and you might then end up with the old license plate holes showing.

I re-epoxied the insides after enlarging the cut-outs to keep everything waterproof.

When it came to wiring up the lights, I naturally kept the color codes the same:

  • Black-to-Black.
  • Green-to-Green.
  • White-to-White.

And that was a big mistake!


The manufacturer of my coach wired the lights wrong. They wired the turn signal/brake lights to the low-brightness bulb, and the tail lights to the bright bulb, so when I matched up the color codes, the brighter tail-lights masked the brake/turn signal lights... definately a safety issue.

The reason I never noticed this before is the old lights allowed you to insert the bulbs in either way (which means the bulbs were inserted in the reverse orientation). However, the new lights have bayonet type bulbs with one pin lower than the other, so they will only insert one way, and that way puts the brake/turn signal on the low-power bulb element. Stupid, stupid, stupid.


How incompetent can these bozos be? Yet again, we must suffer through an incompetent and un-caring RV industry.

After cutting the new area and sealing the cut-out (and old mounting holes) with epoxy, I made the connections to the new light by soldering them, and using marine-grade (adhesive) heat-shrink. Finally, I used marine-grade clear silicone to seal the new lights to the coach.


Repair Video.



One advantage of the Bargman 84 series lights is that you can buy LED modules for them, so I may very well upgrade the lights to LEDs in the future.


Items used in the repair:



Tail Light LED Upgrade.


Six months later, after the leak problems were solved, I decided to upgrade the lights with LEDs. This can be tricky, as there are three potential problems with upgrading tail lights:

  • Obtaining DoT (Department of Transportation) approved lights. Just replacing the tail lights without DoT approved LEDs might not meet safety standards, putting yourself at risk.

  • Slow Blink problem.

  • Vehicle Diagnostics reporting burned out bulb.

For the first issue, there is not a whole lot you can do other than obtaining DoT approved lights. The Bargman LED assemblies I used are approved.

A "slow blink" condition is due to the use of blinker mechanisms having 100yr old technology. They depend on the lightbulb's current demand to open and close a bi-metallic strip.

The strip is sized so that as current going to the lightbulb flows through the strip, it heats up. When sufficiently heated, the two different metals on the strip warp at different rates. The "tips" of the strip contain a set of contacts that open when the metals warp, thus turning the lightbulb off, allowing the strip to cool down, and allowing the contacts to close again, repeating the cycle.

This then means the blink rate is directly proportional to the current demand of the tail lights.

Since LED tail lights reduce the current demand significantly, they will often cause the blink rate to be too slow since it takes longer to heat the bi-metallic strip enough to open. This can be alleviated by upgrading to an electronic blinker.

Vehicle Diagnostics. Some vehicles are capable of reporting a burned out bulb. When swapping out tail lights to LEDs, again, due to the much lower current demand, may trick some vehicles into thinking the tail light has burned out, and as a result - reports a diagnostic condition.

This is alleviated by the use of a resistor kit, which draws the same amount of current that an incandescant light bulb might (around 2Amps). This resistor kit is wired in parallel with the LEDs. Essentially, this approach is wasting energy, but there is otherwise no way around it.

Fortunately, my 2011 E-450 chassis has neither issue, so I did not need a blinker upgrade or a resistor kit.


LED Upgrade Video.

  LED Upgrades:




Last reviewed and/or updated Oct 20, 2017