There's a link to a pic included below.
Follow this 4-step logical progression and tell me if you think it makes
sense. Obviously a call to Bargman should clarify everything. I plan to
call them on Monday.
1 - The part number on my fixture is 30-84-022, which tells me it's an
84 series fixture.
2 - I found an RV forum where a poster said he replaced his 30-84-022
with a 47-86-101 LED fixture and that it was an exact fit. I've looked
at the Bargman site and it looks like the 47-86-101 should work, but
mine is an 84 series, so I'm not sure.
3 - The replacement part listing for the 47-86-101 shows just the LED
lens with a part number of 47-84-420. Note the "84". This is just the
LED lens with bare wires.
4 - Bargman also makes a "upgrade" LED lens with an 1157 plug that fits
the existing socket in my 30-84-022. The part number is 42-84-410.
If the replacement LED lens (47-84-420) for the full replacement LED
fixture (47-86-101) is nothing more than the upgrade LED lens
(42-84-410) without the 1157 plug, it would be a waste of time for me to
replace the entire fixture and have to wire it in. As long as the socket
is in good shape, why shouldn't I just buy the upgrade LED lens? Two
screws, a "bulb twist" and I'm done.
Am I'm missing anything in that thought process?
So unless you have a new trailer, why not just replace the whole socket
assembly. Sockets deteriorate over time. Some of the new lights are much
nicer than putting a plug in bulb in. They over more leds so if one
fails you still have others.
On Fri, 16 Aug 2013 18:34:15 +0000 (UTC), DerbyDad03
The 2 volt drop at the plug indicates undesized wiring in the tow
vehicle or poor connections. I'd bet on a combination of the two. The
scotchlock connectors used by most installers are CRAP and make a high
resistance connection - and most cars are wired barely heavy enough to
handle the OEM lighting load.
As for the extra drop to the lamps on the tailer, most likely ground
issues - 2.5 ohms on a 12 volt 36 watt tail lamp circuit (3
amps)will cause a voltage drop of 7.5 volts, so if you DO have a 2.5
ohm resistance in the ground the trailer has to be getting part of
it's ground through the ball hitch.. I'd take a set of good booster
cables from a good clean spot on the trailer frame to a good clean
spot on the tow vehicle frame and see what it does for your voltage at
2.5 ohms is a lot when you're talking about 12V systems; V=IR so if you
are pulling an amp or more (extremely possible, unless you are using LED
lighting on your trailer) that's a 2.5 volt drop right there. Time to
break out the deoxit, abrasive of choice, and some grease...
if the trailer is steel you might want to just go ahead and run a ground
wire connecting all the ground points together.
I would buy ONE and just try it......
Although if the trailer is older I would just rewire it, add dedicated grou
nd wires to not only the trailer but the tow vehicle, with proper soldered
wires and heat shrink tubing.....
like i said if the traier is older sometimes its best to start over...
the side marker lights arent as likely to have wiring troubles since most o
f the wiring is up high away from rain water and deicing chemicals.... but
still replace them with Leds. Look at this as a one day interesting project
. while your at it fix anything else thats broke or failing like hinges and
locks, and check the underside and roof for rust, and check the ires if th
ey are old replace them and repack the wheel bearings.... while checking th
e trailer jack and restraint chain/////
a few years ago a tree chipper trailer came loose and killed 3 or 4 people.
maintence is key to safe operations
I found one trailer with flakey lights where much of the wiring was rotting
away. undoubtedly from salt water exposure
Other people have mentioned the tow vehicle ground. I have a question...
My tow vehicle has a factory installed connector in the wire harness for
the trailer wiring. This cable and converter plugs right into that
With that setup do I need to be concerned about the vehicle ground or
anything else related to the vehicle wiring? Is it (normally) safe to
assume that the factory installed harness is properly wired?
I'm way ahead of you, Bob!
The lights were the last task in my periodic maintenance exercise. The
tires are fine and inflated to proper pressure - including the spare, the
wheel bearings were repacked, the hinges and other hardware were removed,
wire wheeled and coated with RustOleum Cold Galvanizing Compound and the
fenders were removed painted. While the trailer was on the jack stands I
inspected the underside, the axle, etc. I checked the safety chains and
their connection at the trailer. It all looks good.
Funny story about the jack. I've been using a wheeled jack for years. It
sure makes it easy for me to move the trailer around in my driveway. A few
years ago I found that after I swung the wheel down, it would hold the
trailer up but as soon as I tried to move it, the jack would start to
collapse. Turns out that the nut end of one of the carriage bolts that
holds the jack to the pivot plate had sheared off and the part that was
left just barely caught. It was fine while in the vertical or horizontal
position, but as soon as any lateral force was put on the bolt, it shifted
just enough to move out of the pivot plate and cause the jack to collapse.
You couldn't tell that the bolt was sheared unless you stood directly over
the jack and looked down into the space where carriage bolts came out of
the back of the pivot plate. It all looked good from the outside. It's now
one of the things I check on a regular basis.
So, now, the only thing left to deal with are the lights. My only real
concern is the brightness of the tail lights. Rewiring has long been on my
list of things to do, but if an LED upgrade will improve the tai lights,
I'll be satisfied for now. I've got an 900 mile round trip to my daughter's
college in a couple of days and don't have time to rewire the trailer
before then. If the LED's are brighter with the existing wiring, then
they'll already be there when I get around to the rewire.
It's going to happen, I just can't say when.
try running a wire directly from the tow vehicles battery ground to the trailers frame..... and the ground terminal of the plug....
if the lights get brighter then the ground is a issue and best fixed before you leave....
you could run a semi permanent ground wire for this trip till you fix it permanetely. some contact cleaner on all parts of the plug cant hurt.
taske a close look at the 2 parts contacts, they may be eroding away...
I spent some quality time with the trailer today and here's what I found.
First, the replacement 1157 LED bulbs didn't work very well. It's not
that weren't they bright enough, the problem was the directionality. The
socket inside the fixture is positioned such that the bulb "lays flat"
as opposed to pointing straight out. The incandescent 1157 bulbs spread
the light across the entire lens. The LED bulb acts more like a
flashlight, only lighting up 1/4 of the lens in the direction it points.
In fact, my wife thought the LED side was out until she stood directly
behind the trailer. While the section that was lit was a little bit
brighter than the incandescent, she said she would rather be following a
trailer with the incandescent than the LED. I also tested it at night
and about 3/4's of the lens was lit up, but there was still a dark void,
unlike the incandescent who's lens was fully lit.
OK, so now I decided to look into the ground situation.
Just so you know what I'm working with, the trailer has the following
- Six GE193 side markers, which are grounded via the screws that hold
them into the trailer shell
- One GE193 license plate light, which is grounded via a pigtail to a
self tapping screw into a trailer frame member.
- Two 1157 (dual filament) tail/blinker/stop lights. The left side is
grounded via a pigtail to the same self tapping screw as the license
plate light and the right side is grounded via a pigtail to a self
tapping screw into a trailer frame member on the other side of the trailer.
- One 1156 (single filament) bulb for an interior light in a switched
fixture which is grounded via a pigtail to the same self tapping screw
as the right tail light.
The following tests were all done with the trailer disconnected from
the tow vehicle hitch to eliminate the hitch connection from the
equation. The only connection was the vehicle flat four to the trailer
flat four. The vehicle flat four cable is attached to a factory
installed connector in the vehicle's wiring harness and uses this cable
When I started testing, I had removed the LED bulbs and the tail light
sockets were empty. The side markers, license and interior bulbs were
The first thing I did was disconnect the ground wire that went from the
trailer's flat four to the trailer's tongue, removing the trailer's
frame as the ground. I ran a dedicated ground wire from the trailer's
flat four to one of the rear tail light assemblies. When I turned the
tow vehicle lights on, the voltage read 12.85 V at that tail light.
Obviously, no lights came on because there was no bulb in the tail light
socket and the rest of the lights had no ground.
I then ran a pigtail from the tail light's ground to the ground screw at
the rear of the trailer that normally supplies the ground for that tail
light and the license plate light. That screw goes into the frame of the
trailer. When I did that, the side markers and license plate lights came
on and the voltage at the tail light dropped to about 11 volts. When I
inserted the tail light bulbs, the voltage dropped to the 9.5 V that I
had been reading without the dedicated ground.
That tells me that whether I use a dedicated ground from the flat floor
to the tail lights or use the frame as the ground path, I'm still going
to get that voltage drop.
I then ran a dedicated ground directly from the battery's negative
terminal to the tail light. There was no improvement. 12.85 volts with
no bulb in the tail light socket and the rest of the trailer not
grounded. As soon as I added a pigtail to the trailer frame, the voltage
dropped almost 2 volts. Then when I put the tail light bulbs back in, I
was down to the 9.5 level.
I went around the trailer pulling side marker bulbs and each time I
pulled a bulb the voltage at the tail light went up by 0.2 - 0.5 volts.
It was not consistent which tells me that each bulb was drawing a
slightly different amount of current.
I think the next test is going to be to start running dedicated grounds
to each fixture and see what happens. Since each fixture that uses the
trailer frame as ground added to the voltage drop, there doesn't seem be
a single cause for the drop, i.e. it's not one bad fixture causing the
Heck, as long as I'm running all those grounds, I might as well just
rewire the whole trailer. Running the extra ground wire to the side
markers won't be that hard, but since the current ones are single wire
fixtures with self tapping screws, I'll either need to use a nut, bolt
and lug for the ground or replace the side markers with 2 wire fixtures.
I just wish I knew before I started rewiring whether or not a dedicated
ground to each fixture is really going to resolve the voltage drop
issue. Running a temporary ground wire is as much a pain as rewiring
since there is really is no good way to attach the ground to the current
side markers unless I make up bunch of clip leads and clip the ground
to the ground bracket on the housing.
Maybe I should just do all my driving at night. The lights are easy
enough to see when it's dark.
I doubt the ground is the problem, given the tests you have done. What
is the voltage from the tail-light connection to ground when the
lights are lit? If it is 9.5 volts, the problem is in the tow vehicle
wiring. Use voltmeter from the connected trailer plug to the
tail-light on the car. If over 1 volt (I like to see less than .2) the
problem is in the trailer wiring connections. If voltage at the tow
vehicle tail light is also low with the trailer connected it is a
problem with the main tow vehicle wiring.
Please clarify what you mean by "use a voltmeter from the connected trailer
plug to the tail light on the car".
From what pin on the trailer plug? To what on the tail light on the car?
And if the problem is with the tow vehicle wiring, what is the problem?
What would I be looking for if the voltage you want me to check is over 1
Souns like a inadquate wire size or poor connections; crimping, screwed
down with star washer, rust causing poor conductivity, etc. I don't know
how old the trailer is. When I had my fiver, I used to inspect wiring at
start of every camping season. if something is ??? I remedied
it. And LED needs good diffuser lens, reflector to be effective. LEDs
comein many different forms, shapes, specs.
On Mon, 19 Aug 2013 04:42:33 +0000 (UTC), DerbyDad03
From the wire that feeds your taillights at the plug to any of your
tail-lights on the tow vehicle. You want to do a "voltage drop" test.
It will show if there is resistance between where the tow vehicle
tailights get their power and where the trailer gets it's power -
which boils down to the adapter wiring. If you have no voltage drop
there, check the voltage from ground to the tow vehicle tail light -
if the voltage is low there, you have bad wiring or a bad switch in
the tow vehicle.
On MOST cars without a trailer towing package, you are smart to
install a relay box (or electronic equivalent)) and feed it with a #6
wire from the battery (fused) and have the tail lights, signals, and
brake lights on the trailer fed by the relays, and the relays turned
on by the equivalent circuit on the tow vehicle. You can put the relay
on the tow vehicle, or if you also run a live feed to the trailer, you
can put it on the trailer (which means it is good for more than 1
vehicle, but any tow vehicle MUST have a live feed to the trailer)
Good idea also to have the live feed relayed so it is only on with the
ignition to prevent power leakage and corrosion in the circuit - and
having a switch so you can disconnect the power to the hitch is also a
good idea (again, so nothing is live back there to encourage corrosion
when not connected to the trailer)
I assume that you want these readings taken without the trailer plugged in.
The reading is between 0.071 and 0.084 V. It varied each I started the van
and varied from side to side.
I checked it using both grounds, the ground on the flat four and the ground
at the bulb socket. 13.24 volts at the tail light using both grounds. 13.3
volts at the flat four plug using both grounds.
Resistance reading from tail light ground to flat four ground with the tail
light bulb out reads 0.5 ohms.
Seems to me that the problem is in the trailer, correct?
You have just demonstrated why a lot of these after market lamp
replacements, particularly LEDS are not certified for use on the road
in most counties of the world.
On top of that at least some countries require WIRE ground connections
back to the vehicle .
The tow ball is not accepted as a connection.
I doubt adding wire grounds will fix the problem.
As I see it you still have a single bad connection and every lamp you
add increases the drop.
You should be able to measure the drop across each connection (less
than a volt) then one of them will be higer and you have got your
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