We traveled about 100 miles yesterday. When we left, everything in
the rig worked fine. Both heat pumps, water heater, microwave,
washer/dryer combo, etc… Since we were in a hurry to get checked out
of the campground and off to church, we had a load of laundry to dry.
No problem, just bring up the generator and let it dry while we’re in
service. Worked like a charm.

Unfortunately, when we arrived at our next site, not everything
worked. The rear heat pump was working fine but, the front just clicked
- no fan, no heat, nothing else. At first, I assumed we had a problem
with the heat pump and figured I’d deal with it later. It was late, I
didn’t want to go out in the dark, up on the roof, and take the cover
off to deal with it. So, I turned on the furnaces instead and called it
a night.

A new day brings new ideas

The next morning, we were getting ready to clean up the dishes from
breakfast and noticed we didn’t have any hot water. Odd. Two failures
at the same time? Unlikely. So, it was time to do a little homework. I
took a peek at our incoming power and noticed we weren’t pulling power
on both legs.

Surge Guard Panel

Now, there are a few possibilities for why power is only coming in
on one leg:

• A poor connection at the post – shows voltage but not enough
  “copper” to drive the load
• The Surge Guard has given up the ghost and one leg is dead
• The transfer switch has a stuck contact
• A wire is loose somewhere within that leg
• There are no loads on that leg

Simple to hard

Since I’m a firm believer in tackling the easiest problems first, I
went out and checked the connection at the post. The connections were
clean, no corrosion or burning, and the box felt ‘tight’ – i.e., the
plug didn’t fall out under it’s own weight. So, the post appears fine
on the outside as does the post-end of the cable.

Next I checked the connections inside the power bay. A couple more
plugs to verify and they were fine, too.

At this point, I figured I’d have to open up the boxes and start
checking wiring. I headed inside to get my tools when a thought struck
me – if it’s a contact on the transfer switch, maybe forcing it to
select another source will free it up. Hmmm… How can I get another
power source? The generator! (a.k.a., genset)

With the heat pumps off, I started up the genset. After a few seconds,
the transfer switch flipped power to the genset in lieu of shore power.
After a couple minutes warm-up time, I turned on the heat pumps. Viola!
Both worked perfectly. Now, for the moment of truth. I shut off both
heat pumps and gave the genset a few minutes to cool. Then, I shut down
the genset and tried the heat pumps. Success! Not only were the heat
pumps working again, but our water heater was back in business on
electric.

It was a good morning.

If you ever find yourself with only some of your electric working while
on shore power, it could be a contact is stuck in the transfer switch.
Turn off your loads, start your genset and warm it up, then turn on
your loads (but don’t overload your genset) and observe whether or not
the non-working items are now functional. If so, then turn off your
loads, let the genset cool down, then shut it down and return to shore
power. Now, try your loads again. If the contact was freed up, then
your power will be back to normal. If not, the issue may not be
in the transfer switch. It’s still possible that the contact is frozen
in place.

Dig deeper or…

At this point, you’re going to have to open up your electrical system,
tracing wires back from the power bay to the circuit breaker panel to
each item until you find the cause. If you’re not comfortable with
electricity, this is the point where you hire a certified RV repairman
to take over the task.

I hope this helps someone avoid what could be a costly service call for
a simple fix.