No power to 3 plug ins

Is your unit a 50amp unit? If so it sounds like you are only getting only half of the of the 240v. The way it works is you have 2 - 120v legs of power or phases. When one goes out then half the unit would not work. Your shore power could be the issue, your hookup cord, or your main breaker. If you have a volt tester i would test the shore power first to make sure you have 240v there. Then plug in your cord to the shore power and check to see if you have 240v there. Or if you are comfortable with it, i would open my breaker panel and check the power at the main breaker.

First, I'm not a Coachmen RV Tech. (but most DC to AC inverters are not brand specific.)
* Check inverter fuse (on actual inverter frame). Replace.
* Check DC voltage at inverter. Should be 12 (or 24 VDC) depending on your system battery supply and inverter.
* Check the DC cable connections; crusty, dirty? Cut all power. Remove and clean terminals. Re-connect and check.
* DC okay? Check 110 VAC power at output of inverter. No power? Replace inverter. (possible power spike damaged it or it over heated)
* 110 VAC okay? Check the power panel breakers. If stuck in middle then turn all the way off to reset and turn all the way back on to activate. Check AC power at outlet(s)
* Still no power (at outlet)? Check all outlets. If some still works then there is a problem with the power (wires) distribution. You will need an electrician to trace the wires back to the break in circuit.
* Be safe. check your warranty and call for service.
* Note; your inverter may be on a separate warranty.
Aloha, ukeboy57

Your trailer has two electrical systems, 12v and 120v. The 12v system has a battery and perhaps a converter/charger to power it. The 120v system must he hooked up to 'shore power.' Both systems have their own protection. The 12v system has a fuse panel, check for power at each fuse. 12v wall switches are often smaller and don't look like typical 120v switches like in a house.

The 120v system has a breaker box and circuit breakers. Reset each breaker by turning off then on again. In addition, the 120v outlets might have a GCFI outlet near a sink. It often is wired first in a breaker circuit, thus giving GCFI protection to other outlets in the circuit. Test the GCFI and make sure it clicks off and can be reset.

You didn't indicate, but I will assume when plugged into park power your 110V AC devices (Outlets/TVs/Microwave) work?

If so that isolates it to the genset or something up to your AC/Breaker distribution panel.

Things to check in the main power from the generator to electrical main AC distribution/breaker panel:.
Some type of Breaker off at the Genset (Blown fuse?)
Some type of toggle switch/transfer switch on the wrong position
If you have a auto transfer switch it might be stuck or defective
Loose connection or a connector coming loose
Defective wiring

Contact your local retailer directly or online here:

You have a main breaker in the panel, most often 30 amps. (Possibly 50, depending on your hookup. If your cord you plug in outside has 3 prongs it's 30 and 4 prongs it's 50) then you have a 20 amp breaker for your air conditioning and a 15 amp for your microwave or outlets. As far as fuses go, usually you have a 30 or 40 for the main converter fuse(s) and then mostly all 15's in all the other slots.

120-
VOLT
AC
SYSTEM
The following electrical components (if so equipped) will only operate when your
RV is connected to shore power: 120 to
12-volt power converter, air conditioner,
120-volt refrigerator, microwave oven, television(s), fireplace and appliances
plugged into convenience receptacles.

SECTION 6 - ELECTRICAL SYSTEM JAYCO TOWABLE
6-2
120-
VOLT
CIRCUIT
BREAKERS
The 120-volt AC circuit breakers located in
side the main load center protect all
120-volt wiring and components in the RV fr
om circuit overloads and short circuits.
Should a circuit overload or short circui
t occur the circuit breaker protecting the
affected circuit will "trip" preventing the flow of electricity through that circuit.
If a circuit breaker trips, shut "off"
the appliance on that circuit (i.e., power
converter etc.) and allow the circuit breaker to cool down for a brief period of time.
After the cooling down period, reset the circuit breaker by moving its lever "off" and
then back to the "on" position. If the circuit breaker re-trips or frequently trips,
contact your dealer to have the electrical problem diagnosed and repaired.
A circuit breaker identification label is permanently attached to the inside surface
of the 120-volt load center.
Maintenance and Replacement
At the beginning of camping season, inspect the circuit breakers and replace as
needed. Test by turning each circuit breaker "off" and back "on". Circuit breakers
are wearable parts and must be replaced
as needed, as part of your RV
maintenance. If you have any questions, consult your dealer.
Please contact your dealer for repair assistance when replacing circuit breakers.
CONVERTER
The power converter converts 120-volt AC power to useable 12-volt DC power
when the shore power cord is connected to an external power source.
The converter has a built-in protective thermal breaker that will shut it down should
overheating occur. Overheating can be
caused by operating the converter above
its maximum power output for an extended period of time, or by an obstruction to
its ventilation air flow. To reduce converter heat build keep unnecessary 12-volt
lights and motors turned "off"
.
Keep the converter cooling fins and fan clear of
obstructions.
Inspection and maintenance
If the 12-volt power converter is not working (auxiliary battery not being charged)
check the reverse polarity fuse(s) in the converter fuse panel.
There are no
customer serviceable parts inside the converter case and the
manufacturer's warranty will be void if
the case has been removed
. If you
have further concerns contact your dealer.

Is it the AC or DC? If AC find the AC panel and locate the tripped circuit breaker. Or look for the default (electrical outlet / plug) located in the galley or bathroom. If the DC is out then there are some fuses to look at.
If all else fails then review the owner's manual that came with the rig.

Do you have good power that the outlet. I have seen many issues at RV parks of not having sustained power or one leg of the breaker going bad causing loss of power. If you do have good power coming into the surge protector but not out. Then go through the reset procedures for the surge protector. If it will not reset, then the surge protector has failed and will need to be replaced. If power is coming through then check the main breakers in the coach for possible failure. Breakers can trip but still look as if they are properly set. Turn them completely off then back on to reset.

is it possable that these 3 circuits are 110 volts and you are switching to 12 volts so it cuts them out ?