F.A.Q.'s
Electrical
Q: I have an early 1960's trailer. Do you have a schematic of
the wiring on this trailer?
A: There were no owners manuals until 1964, that is where
this information would normally be. Since a schematic is critical to restoring
and maintaining your Airstream, it is a good idea to create one, mapping
out your wiring and understanding where everything goes. A Test Light
and a few alligator clip pig-tails will help.
Q: Where can I get replacement Marker Lights?
A: A cheap looking replacement for the Teardrop style
is made, and the later oval Grote lights are still manufactured by Grote.
Both can be purchased at Airstream and RV dealers.
Q: I have an old trailer in which the clearance lights and taillights
don't work and no schematic. How can I track this down?
A: Schematics weren't published until 1964. However,
the following general suggestions have proven helpful in the past:
1) In trailers of this age, the wires coming from the tow car pass down the tongue via a pigtail to a junction point above the belly pan a few inches in back of the front of the body shell. There is an inspection cover in the belly pan at this point. From this point, the wires run back to taillights and over to the Marker Lights and the brakes if equipped. At, or near this point is a ground to the trailer shell. A faulty ground shows up as no lights working when the trailer is unhitched. Make sure this ground connection is OK.
In the 1950 era trailers , the junction point was inside the wall just above where the harness wire goes in to the belly skin.
2) In checking circuit continuity, use a light bulb, not an ohm or voltmeter. The reason: A fragile (high resistance) circuit may appear good by the meter, but it is not good enough to light a bulb.
3) Bulbs often are corroded into the sockets. Use WD-40, or crush and replace the bulbs. Clean all contact surfaces. Replacement bayonet sockets are available from RV Dealers.
4) All grounds to the trailer shell are suspect. Wire in new ones frequently. You can't have too many. The rivets that hold the Marker Light bases in place are suspect, as they are used for the ground. Replace these or install short jumper wires.
Q: Were Airstreams made with aluminum wire? Must it all replaced?
A: Certain years between 66 and 68 used aluminum for
some of the primary wiring. One cannot connect aluminum wire to devices
or connectors that are not rated for AL-CU usage, such as the circuit
breakers and outlets and switches. Where the aluminum and copper parts
touch together a chemical reaction occurs which forms an insulating layer
between the two, not at all what you want in an electrical circuit. You
have choices:
1) You can arrange that only copper wire ties into these CU only rated parts. You can do this by interposing short pieces of copper wire at the box, making the copper to aluminum connection (wire to wire) a short distance away using a special type of bimetallic connector lug and gel compound made for this purpose.
2) You can replace all the wiring with copper.
3) Or you can replace the circuit breakers, connectors, switches and outlets with those rated AL-CU and use the dielectric compound. You still must make the connectors to pigtail components such as motors and some lamps with the special connectors. Ask an electrical supply house or electrician for help on something as important as this.
Q: What is a Uni-volt?
A: A Uni-Volt is a brand-name for a power converter system
used by Airstream. The system was first used about 1964, and is used to
provide 12 volt DC power and 18 volt AC power to the trailer from 100v
shore power. Being a ferroresonant converter, it will hum. Some people
turn theirs off at night. It is basically a power reduction transformer,
AC to DC rectifier with filter capacitors. The 12VDC volts is used to
supply the light fixtures and the 18VAC for the fan motors. When not connected
to shore power, the trailer battery is used to supply 12VDC to these users.
The 12VDC went to the lights and the 18VAC went to the vent and pump motors.
A 12 volt light bulb works equally well on 12 volts DC or AC. But a 12
VDC motor, if used on AC must have 18 volts supplied to it to function
correctly because the effective DC voltage of 18VAC is 12.7 volts.
Q: How do I determine if my Uni-volt converter is working?
A: With the Uni-volt off, measure the voltage at the
battery. It should be 13.8V +/- 1V. Turn the converter on - the measured
voltage should increase by about 0.5V.
The only part that routinely goes bad is the capacitor. Usually is 25
uFd at 600 volt AC. You should be able to get one at a motor rewind shop
or maybe an air conditioner repair place.
Q: Does the Uni-volt charge the trailer battery when connected to shore
power?
A: The first Uni-volt systems introduced in 1964 did
not, it was not until later when they added a regulated charging circuit
that they did - and even then only on the larger trailers. On the other
trailers, the tow-vehicle charging system is the only source of re-charge.
Q: Where can I get replacement lenses for the Bargman 99 "Wedding
Cake" taillights?
A: They are no longer available. Reflect-O-Lite lenses
were a universal replacement, available at auto/truck parts stores until
about 1995. Signal-Stat made a bus light that was close in design, and
required replacement of the whole assy, but they too are discontinued.
You may find some old stock of these. AirstreamDreams
sells reproductions from a waiting list.
Q: I think my older original recessed Bargman “9” taillights
(#11 lenses) are wired for 6 volts still. What can I do?
A: These were originally 6 volt lights with independent
turn and stop elements in addition to the tail (running) light. The easiest
fix is to replace the socket pigtail with a single contact type and replace
the bulbs with 12 volt equivalents. Cap off the unused circuit for the
old brake light circuit.
Q: Someone dealt with the 6 volt issue by replacing the Bargman
9’s with cheap replacements. What can I do?
A: Signal-Stat makes a similar recessed truck light with
a chrome ring that looks pretty close. The part number is #3612.
Q: My flush mounted porch light is melted looking. What can I do?
A: This is also called a "scare" light for
some reason. It is really just a back-up light made by Signal-Stat, and
if left on for real long periods of time, the lens will melt. Replacement
lenses and lights are still available from Signal-Stat at truck part stores.
Q: My rear license plate holder and light is rusted out. Where
can I get one?
A: The one used from 1958 to 1968 was made by Signal-Stat
(part # 435W), and is still available from truck/trailer part stores and
the Internet.
Q: Our 1948 Liner has just a single taillight in the middle. Is
this legal?
A: It used to be until the early 1950’s, when federal
laws were passed requiring turn indicators. This early single light was
called the “Universal Night Owl" and contained a stoplight,
taillight with license plate illumination. The early retrofit for these
trailers was the use of “Yankee Turnmaster” lights, added
to the outboard corners of the rear. Conventional all in one lights started
appearing in 1951-1952. The older trailers were grand-fathered, but even
they too were required to have lights installed. This may mean your trailer
hasn’t been licensed or used in decades!
Q: I'm picking up an old Airstream that has an electrical plug
with round terminals. Are the old Airstreams wired different?
A: Yes, but most have been converted over to the newer
connectors and wiring layout. If by chance it hasn't, you can convert
it to the current standard as shown on this Marks
RV info page.
