Fixing mysterious electrical problems

The worst problem you can have with any vehicle is not a total failure. It’s an intermittent failure. Those little quirks that crop up but can’t be reliably reproduced can drive you batty, especially when you haul the Airstream into the dealership and they come back to you with a note: “No problem found,” or “Unable to reproduce customer complaint.”

Of these, the most common are electrical problems. Flickering LED lights, problems with the refrigerator or electric brake actuator (if your trailer has disc brakes), short battery life, and dim lights can all be symptoms of one common problem: bad electrical grounds.

In 12 volt DC wiring systems, every device (light, water pump, fan, furnace, etc.) has a 12v+ (positive) and 12v- (negative) connection. The negative connection goes to “ground” (or “earth”) in British English) to complete the circuit. Generally, all of the ground connections in a travel trailer or car end up being attached to the metal frame of the vehicle.

When the ground connectors get corroded or loose, all kinds of strange problems can occur. Electricity wants to find a path, so if the ground is poor, the current may run in unexpected ways, even backwards through a circuit. This can cause appliances to fail, work incorrectly, or intermittently.

Late model Airstreams usually have one or two external grounding points that provide the main electrical path to the frame. On vintage Airstreams the ground may be inside. Once located, these grounds can be easily checked. On a late model Airstream one is usually toward the front, possibly beneath the A-frame where the propane tanks sit. Look for a thick bare copper wire that is bolted to the frame or to a propane gas line with a small copper clamp. The location may vary—on some trailers it is located near the front curbside stabilizer jack.

If this wire looks corroded or exceptionally dirty, unscrew the clamp that holds it in place and clean up the clamp and wire with sandpaper or wire brush. The copper should be shiny where the wire makes contact with the clamp, for a good electrical connection. Don’t paint it!

There may be a second ground wire located inside the rear bumper compartment, which can be serviced in the same way. After cleaning, you can coat the area with dielectric grease (or pure silicone grease) to reduce future corrosion.

Checking the grounds is not just a good diagnostic step, it’s good maintenance that might help you avoid mysterious electrical symptoms later. Since it’s easy to do with just a screwdriver and sandpaper, considering doing this procedure once a year.

Digital Voltage Monitor

Should you care about the power that comes into your Airstream from the campground?

Absolutely. YES.

Even newer campgrounds can have problems with their electrical power. Outlets may be mis-wired or damaged in a way that can be hazardous to your health—and the health of your Airstream.

Especially on a hot and humid day, when everyone in the campground is running their air conditioner, you’ll need to know that voltage is high enough to avoid burning out your A/C compressor.

The best way to know you’re getting good power is to use a digital AC voltage monitor. Outside Interests recommends one of the best: the Prime Products monitor, available at the Airstream Life Store. It constantly displays voltage so you’ll know if the power is sagging, and it checks for common mis-wiring conditions:

  • Reversed polarity (which can cause a very dangerous “hot skin” condition
  • Open neutral
  • Open ground

Digital Voltage MonitorIt’s simple to use: just plug it into any available outlet in your Airstream while you’re connected an electrical hookup, and observe the lights on the display. You’ll always know at a glance that you’re getting good power.

This voltage monitor is something every Airstream should carry at all times, and is available from the Airstream Life Store. When you order from Airstream Life you’ll also receive Rich Luhr’s short instructional booklet, How To Avoid Electrical Problems At The Campground.

The 7-way cable on an Airstream

Most people don’t think about the fat black cable that connects the Airstream to the tow vehicle—until something doesn’t work, like taillights or brakes.

It’s called either the “umbilical” or “7-way” cable, and keeping it in good condition is important because it’s the critical link for correct operation of trailer brakes, lights, and signals.

The 7-way, explained—

Dirty 7-Way plug
Don’t let your plug look like this

Since 1989 all Airstreams have used the same wiring arrangement. (Earlier trailers may have different wiring, but typically they have long since been rewired to fit modern tow vehicles.) Each location in the 7-way plug is dedicated to a specific signal. Two of them—the 12 volt positive and 12 volt negative—supply power to keep the battery charged while towing to prevent depleting the battery while using the electric brakes. The other pins carry signals to activate the clearance lights, turn signals, brake lights, and back-up lights (if the trailer is equipped with them).

Is your cable too long?

Take a look at the 7-way cable the next time your Airstream is hitched up. Does it drag on or very near the ground? It will wear away quickly if it touches the ground during ordinary towing. You can use a bungee cord to take up the slack. (Drooping to touch the ground only in a sharp turn is okay, since that contact with the ground will be very brief.)

The cable should have enough slack so that the tow vehicle can make very sharp right and left turns in a parking lot without pulling the cable taut. If your cable is too short, you can buy an extension cable or (better) have the entire cable replaced. On vintage Airstreams, old stiff cables are common, so replacement is a good idea anyway.

When hitching up…

…double-check that the plug is inserted fully each time. Often it feels like it is in all the way when it really isn’t. To be sure, kneel down and look at the connection from the side. There are little tabs on the plug and the lid of the receptacle on the tow vehicle, which lock the plug into place. If the plug isn’t inserted fully, you’ll be able to see it from the side much more easily than from the rear, and this will ensure it doesn’t come loose while towing and make sparks on the freeway.

Avoid corrosion

Corrosion is the major cause of problems for the 7-way plug. Just a little moisture over time will result in greenish or white corrosion on the connectors, and that will cause problems like inoperable lights or brakes.

Be sure to position the plug between trips so that the head of plug is hanging downward. That will help keep rainwater from settling in the plug. At various RV stores you can find a generic “7-way plug holder” that mounts to the A-frame, which gives you a place to lock the plug when it’s not in use.

Periodic maintenance…

…for the 7-way plug on the trailer is important. Periodically you should clean corrosion from the seven spade connectors. It’s difficult to do without the right tool, so we recommend a kit available in the Airstream Life Store which includes a burnishing tool (a special file designed for electronic use), a premium electrical contact cleaner, and instructions.

You can also use the same tools to clean the connectors in the tow vehicle’s 7-way outlet, if they need a little help. Plan to do this simple cleaning job at least once a year as preventative maintenance. With the right tools it takes just a few minutes.

With those simple checks and a bit of annual maintenance, you’ll have eliminated the most common causes of problems with trailer lights and brakes.

Options for preserving your Airstream batteries during storage

Ed B. from Washington posed a question that might be on your mind, too—

“I’m wondering about replacing the factory converter/charger unit with a ‘smart charger’. Battery management seems to be my problem just now. When in storage, the batteries go down to zip or overcharge, both of which are hard on the batteries. We have no problems while underway.

I tried putting a small charger unit on the batteries while in storage, but the small constant draw seems to fool the charger in to delivering full charge all the time without activating a trickle delivery as it is designed to do. Is this why Airstream has not put ‘smart charging’ units in at the factory?”

The converter/charger that Airstream installs works very well for the vast majority of cases. It is perfectly adequate unless you (a) want integrated inverter capability; (b) switch to AGM or other type of batteries; (c) want a faster charge rate, or some bells & whistles; (d) add a lot more battery capacity.

Before you spend money on an upgrade, try a few other basic steps:

Battery disconnect1. During short term storage, use the “Battery Disconnect” switch to cut off demands on the battery (except the propane leak detector).

2. During long term storage, disconnect the battery cables and put the trickle charger on. Make sure what you have is really a smart trickle charger designed specifically for storage of batteries and not simply a battery charger with a “float mode”. If the latter, then all you’ve done is replace your Airstream’s charger with another one that is doing exactly the same thing.

3. As an option, if your Airstream is stored outside, consider a solar panel and solar charge controller. A 100 watt panel would be plenty to keep your battery happy under average conditions.

4. Make sure you are maintaining the water level in the batteries during storage. Consider switching to AGM batteries. These will not “boil off” (lose water) during charging cycles so you don’t have to check the water level during storage, and they last longer.

5. If you have the ability to measure current draw on the battery while the trailer is stored and the Battery Disconnect is switch to “STORE”, do so. Parasitic draw may account for up to half an amp, but if it’s higher than that you have a voltage leak or device that isn’t working properly, and that will kill the battery pretty quickly.

Solar vs Generator?

Lots of new Airstream owners want to find ways to extend their camping time while “boondocking,” (off-grid camping, away from electrical hookups). So inevitably the question comes up: which is better, a generator or solar panels?

Generator AirstreamThe answer comes down to your needs. Generators are the most practical way to have enough power to run very high-wattage appliances like the air conditioner and microwave oven. If you must have air conditioning when not plugged in, you will have to use a generator, and it will need to be capable of at least 2,600 watts peak output, and preferably 3,000 watts.

However, if you can live without your air conditioner and microwave oven, solar panels become a very attractive option. Solar panels are silent, don’t require you to carry fuel, and are virtually maintenance free (other than washing them once in a while). They work without any intervention from you and can keep the batteries in your Airstream charged while it’s in storage.

A major difference is that solar panels only provide power to charge the batteries. They don’t directly power anything, although the batteries will of course power all of your 12-volt devices and can even power low-wattage 120-volt AC appliances like laptops and TVs using an inverter.

Most RV generators have on-board inverters so that they can provide 120-volt AC power directly to the Airstream, just like plugging in. This is convenient but most of the time the generator is producing far more power than you actually need.

If you want a generator primarily to recharge your batteries while camping off-grid, you can get the smallest generator possible. Even a small 1000-watt (rated) generator can typically produce far more power than the batteries will accept at any given time. The rest of the power is wasted, unless you are running the microwave or some other power-hungry AC appliance while the generator is running.

This means that the best time to use the generator is when power demand is high. It’s much easier to avoid using battery power by being plugged into the generator, than to try to recharge battery power later. Use the generator in the morning and evening when you are cooking and using lights and water pump, and the power needed will be supplied by the generator rather than coming from the batteries.

If you want to get a generator, do yourself and your neighbors a favor and get one of the quieter models specifically made for RV use. Both Yamaha and Honda make excellent products which have good reputations for reliability and quietness. If you borrow a “construction” generator from work on your weekend camping trip you will save some money but you won’t be popular when you fire it up—and the noise might detract from the peacefulness of your boondocking site, so what’s the point? Similarly, there are cheaper “knock off” brand generators on the market, but their quality is not up to the standards of the major brands.

Solar’s big advantage is in recharging batteries, so if extending your time at camp is your primary goal, they are the preferred option. Rather than pumping out large amounts of power in short time periods like a generator, solar provides a steady all-day charge will have a much better chance of getting your batteries up to 100%. It’s like the turtle and the hare. With batteries, slow and steady wins the race.

If you have both a generator and solar panels, use the generator when the batteries are heavily discharged (for an hour or so in the morning, for example) to get the bulk charge done quickly, and then let solar finish the job over the course of the day.

If you only have solar, keep in mind that during the morning and mid-day, moderately or heavily discharged batteries will probably accept every amp the panels can generate. Then the charging rate naturally slows down. If the sun is still shining at that point you have surplus power, and so that’s the time of day to plug in all of your rechargeable accessories like phones, cameras, laptops, etc. This strategy takes maximum advantage of the power being generated.

Sometimes people go with generators over solar because they are afraid they won’t have power on a cloudy day. Certainly clouds will drastically reduce the amount of power generated, but you’ll still get some. The solution is to add batteries so that the Airstream has enough power to bridge a cloudy day (or two) without a problem.

If you are considering adding solar panels, keep in mind that the solar panels should be sized to approximately match the capacity of the batteries in the Airstream. If the panels produce a lot more power in a typical day than the batteries can store, you’ll have wasted money on expensive panels. If the panels are too small, they might not produce enough power to keep the batteries charged, which can lead to short battery life if the trailer is not plugged in regularly (such as during long-term storage).

It’s hard to do an apples-to-apples comparison of generators and solar panels, because as you can see, they perform very differently. It’s even hard to pin down a cost for comparison, because the output of each option can vary widely. Quiet RV generators from Honda and Yamaha range from 1,000 watt units suitable for battery re-charging and small appliances, up to big 3,000 watt units to run the air conditioner. Solar panel systems (including battery banks) can run from 50 watts up (typically 200-400 watts will fit on the roof, plus more possible using portable panels), and the costs of an installed system are likewise varied. Keep in mind that comparing wattages is not useful since the solar panel runs whenever the sun shines, and the generator usually only runs for short times.

You’ll need to decide which option you prefer, and then talk to a solar installer, or shop generator prices. RV solar specialists are in many parts of the country (some are even mobile and will come to you) and they can help determine the optimal size of your battery bank and provide solar panels to match.

Either way, upgrading your Airstream to give you more boondocking time is a great advantage. It will open up new travel options for you and eliminate worries about running out of power when on a long trip or during storage.

For more, pick up your copy of Rich Luhr’s books, “The Newbies Guide To Airstreaming” and “Airstream Life’s (Nearly) Complete Guide To Airstream Maintenance” at the Airstream Life store.