09 Electrical Features
General Information
There are two electrical systems in your motorhome. These are the 12 volt DC (VDC) system and the 120 volt AC (VAC) system. Most standard appliances require the 120 VAC system, while the majority of the lighting systems used in the motorhome use the 12 VDC electrical system.
The electrical power for the 12 VDC system is supplied by the batteries of the motorhome. Those batteries are charged by a power converter. The alternator also charges the batteries when the engine is running.
The electrical power for the 120 VAC is supplied by the power cord when the motorhome is connected to an external power source or when the on-board electrical generator is in operation. The converter/inverter can also supply 120 VAC electrical power (to limited outlets and limited appliances)— the inverter transforms the 12 VDC electrical power from the batteries into the 120 VAC electrical power for the basic appliances.
To connect the motorhome to an external source of 120 VAC electrical power, Tiffin Motor Homes recommends that all of the circuit breakers be in the OFF position, (this is done to prevent any power surge when connecting the motorhome to the external power source), and then unwind the power cord from the electrical compartment located in an external compartment. The standard, flexible, power cord supplied with the motorhome is designed to handle up to 50 amperes. Make sure that the pins in the male end of the plug are oriented correctly so that they match the power cable, and that they are in good condition (i.e., are not bent or damaged).
If there is a circuit breaker switch at the “plug” end of the power cord, that breaker must be turned OFF before making the connection. Insert the plug into the mating outlet, and then turn the circuit breaker ON. Close and lock the electrical compartment door to protect the contents and to keep them clean and dry. Close the cover on the power box, if so equipped, to avoid an unintentional disconnection and to keep the contents clean and dry. Then switch the main breaker to the ON position.
When properly connected, the 120 VAC system provides power to all the 120 VAC circuits and outlets when the main breaker is turned ON.
Electrical Cautions
Circuit Breaker Boxes
Interior 120 VAC and 12 VDC breaker boxes (Figure 9-1) are typically located in the bathroom.
 Figure 9-1: Breaker Boxes |
The circuit breakers and associated fuses are installed to protect the electrical system of the motorhome from any overloads. Do not attempt to change the electrical circuitry or to add appliances yourself.
Please consult an authorized Tiffin Motorhomes Dealership or Tiffin Motorhomes, Incorporated in Red Bay, Ala., to determine whether any changes you desire are appropriate and acceptable.
Tiffin Motorhomes’ qualified staff of electricians can readily determine whether any changes sought (e.g., CB radio, amateur radio, satellite television receiver, personal computer system) are possible or not and can advise you onthe matter.
The 120 VAC power supplied from shoreline or generator enters the “MAIN” circuit breaker located on the left side of the AC breaker box. This double circuit breaker will disconnect power from all 120 VAC appliances when tripped. Each circuit breaker has a label giving an indication of the device it is passing power to. The typical items powered from the AC circuit breaker box are:
air conditioners, water heater, microwave, engine preheat, AC receptacles, televisions, Blu-ray player, converter/inverter, and the optional refrigerator.
Check these circuit breakers if a 120 VAC powered device is not working.
The 12 VDC circuit breakers are located on a separate panel near the AC breaker box. There is a placard attached to the panel giving an indication of which items are powered by each circuit breaker. The items that are powered from the DC circuit breaker panel include: all interior and decorative lighting, powered roof vents, monitor panel, thermostats, furnaces, water pump and heater, and passenger side console.
A multiplex based system with power distribution modules supply the 12VDC functions for the chassis functions. These modules and associated circuit protecting fuses/breakers are located in the driver’s side front and passenger’s side rear compartments.
Another panel of circuit breakers is located in the passenger side, external, rear compartment which contains resettable breakers for the following systems: Slide-outs, 12 VDC disconnect system, storage box lights, and solenoids.
Auxiliary Start Switch
The auxiliary start switch (Figure 9-2) is located on the switch panel to the left of the steering wheel in
front of the driver’s-side console box (Figure 9-3).
 Figure 9-2: Auxiliary Start Switch |
 Figure 9-3: Driver’s Side Console |
This switch connects the motorhome coach batteries to the chassis batteries—this allows the chassis batteries to “borrow” power from the coach batteries to assist in starting the engine.
If the chassis batteries cannot start the engine by turning the ignition key, hold down the battery-boost switch for at least 60 seconds and retry starting the engine.
When attempting to use the auxiliary start switch function, Tiffin Motorhomes recommends that you press and hold the switch for about 60 seconds before trying to start the engine. This gives the two sets of batteries (house and chassis) a chance to equalize before engaging the starter. The multiplex system that controls most chassis functions will need to reach optimal voltage range to ensure proper operation as well.
Battery Inspection and Care
 Figure 9-4: House Batteries |
The 12-VDC electrical-power system consists of two 6-VDC batteries wired in a series to provide a final 12 VDC system (Figure 9-4) providing up to 200 Ampere-hours (A-hr) of service.
It is necessary to recharge the batteries occasionally to increase the operational lives of the batteries. It is also necessary to check the external condition of the batteries on a regular basis.
Look for cracks in the battery case and cover. Check the vent plugs and replace them if they are cracked or broken. Keep the battery clean.
Since accumulations of dirt and acid residue around the battery terminals might provide an electrical path for discharging the battery, the area around the terminals must be cleaned periodically.
You can use an old toothbrush and a sparse amount of a diluted solution of baking soda (sodium bicarbonate) and water (distilled or deionized, preferred; tap water, acceptable) to clean and neutralize any acidic build-up around the battery terminals. If this is done and there is any foaming on the top of the battery, this indicates that acidic residues are being neutralized. Rinse the cleaned areas thoroughly with distilled or de-ionized water (tap water is okay, too).
Avoid getting the baking-soda solution into the battery fill plugs to each battery cell; this would drastically reduce the effectiveness of the battery (by neutralizing the sulfuric acid in the battery cells) or, worse, “kill” the battery. Dry the battery cables and terminals to prevent corrosion. To protect those terminals further, use a plastic ignition spray on the terminals. Do not use grease on the terminals, especially on the metal-to-metal connections, as grease might act as an insulator and keep the battery electrical power from entering the cables.
If the batteries are not going to be used for an extended period, remove them from the motorhome and store in a warm, dry place. Tiffin Motorhomes recommends that this service be performed by a qualified service technician, as the process is usually too complicated for the average owner to perform. For those who might wish to perform this service themselves, use the following procedure: Mark the battery cables (“+” sign or “red” for the positive cable; “-” sign or “black” for the negative cable) so that they can be properly reconnected again later. These batteries require periodic recharging to maintain their full charge.
Over time, the batteries will lose some of the water used with the sulfuric acid in the batteries. Following manufacturer’s recommendations as found in the Owner’s Information Package, periodically check the fluid levels in all the cells of the batteries (be sure to use safety eyewear during this process) and fill those that are low with water (distilled or de-ionized water is preferred; tap water is okay).
Do not overfill the cells; follow the filling directions exactly. Check the battery on a regular basis to realize the fullest service possible from the batteries over the longest time possible. If the motorhome is to be stored for an extended period, disconnect the 12 VDC battery system—this procedure will prevent unnecessary drain and corrosion of the batteries and their terminals.
The house batteries are located beneath the entrance door step well. Access can be gained by lifting the middle step tread.
120 Volt (VAC) AC Receptacles
Your motorhome is equipped with several 120 VAC receptacles (Figure 9-5) located throughout the interior of the motorhome. These 120 VAC receptacles are of the “three-prong” variety; the third prong being a grounding pin that provides adequate grounding to protect one from any electrical shock.
 Figure 9-5: 120 VAC Receptacle |
For these receptacles to work properly, do not use an adapter, cheater, or extension cord, which defeats the function of the grounding pin. For the same reason, never remove or bend away the ground prong or pin from any threeprong AC plug so that it would fit a two-prong AC receptacle (i.e., an ungrounded AC receptacle).
Never operate the motorhome if there is an electrical short present, as an electrical short might deliver an electrical shock to anyone being exposed to the exterior of the unit.
If you feel even the slightest of electrical shock, immediately disconnect the unit from the 120 VAC power source and locate the electrical fault (i.e., typically, it is a break in the grounding circuit).
Do not reconnect the 120 VAC power until after the electrical fault is fixed—the grounding circuit must be continuous from the frame to the distribution panel, to the power cord, and to the earth ground so that electrical-shock protection is realized.
12 Volt DC (VDC) Receptacles
Your motorhome is equipped with a 12 VDC receptacle conveniently located on the dashboard or bulkhead (i.e., the “black” connector plate in the figure). This 12 VDC receptacle (Figure 9-6) can be used for providing power to various items, such as cellular phones or personal computers or portable communications equipment. This receptacle is usually found on the bulkhead in front of the passenger’s seat so that it is conveniently available.
 Figure 9-6: 12 VDC Receptacle |
USB Receptacles
The motorhome is equipped with USB ports (Figure 9-7) conveniently located on the front dashboard and in the bedroom area as well as on the passenger console. These ports allow for easy access when charging cell phones, laptop computers, iPods, iPads or other tablets.
 Figure 9-7: USB Receptacle |
Ground Fault Circuit-Interrupt Receptacles
In the kitchen and bath areas, there are 120 VAC GFCI receptacles (Figure 9-8), which provide greater protection against inadvertent electrical shocks.
 Figure 9-8: GFCI Receptacle |
These specialized GFCI receptacles provide both overload and short-circuit protection for the user. The electrical receptacles located in the slide-out are wired through the kitchen GFCI. The exterior receptacles are wired through the bathroom GFCI.
If an appliance plugged into a slide-out or exterior receptacle is not working, check for a tripped GFCI in the kitchen or bathroom.
All GFCI-protected receptacles are marked as such, but only one of them might have two pushbuttons on the receptacle (as shown in the picture). The upper pushbutton is a “test” button, which can be used to ensure that the GFCI function is working.
To reset this GFCI breaker, push the lower button (the “reset” button) to restore power to all the GDCI receptacles on this circuit.
These receptacles protect the user from ground faults between an electrically “hot” wire and ground. The GFCI will not reduce the shock hazard if the short is between a neutral and “hot” wire, or two “hotload” wires. The GFCI must be tested at least once a month. The 120 VAC electrical system must be ON for the GFCI to be tested.
To test the GFCI, the reset button must be pushed in fully before starting the test. Push the test button; this will cause the reset button to pop out, which means that the protected circuits have been disconnected. Push the reset button back in until a “click” is heard—this will reactivate the protected circuit. If the GFCI is working properly, the reset button will remain in the “in” position.
Converter/Inverter
A converter/inverter (figure 9-9) is provided as a standard feature on the Allegro Breeze. This converter/inverter provides these three basic functions:
 Figure 9-9: Converter/Inverter |
- Convert 120 VAC power into 12 VDC power when 120 VAC is available. The converter will create 12 VDC to charge the house batteries when 120 VAC power is available from shoreline or the generator.
- Invert 12 VDC power into 120 VAC power when 120 VAC is not available. The inverter can create 120 VAC to power the entertainment system (e.g. TVs, Blu-ray player) and optional residential refrigerator when 120 VAC power is not available.)
- Transfer 120 VAC power to the inverter loads (e.g. entertainment system, optional refrigerator) when 120 VAC power is available.
The converter/inverter will transfer, or pass, 120 VAC power to its loads when plugged into shoreline or running the generator.
The converter/inverter is conveniently located in one of the compartments located beneath the motorhome. Do not store items around the inverter as these items could cause accidental electrical short circuits or obstruct the cooling fan leading to overheating.*** content from other doc – checking with client
There is a three position selector switch on the converter/inverter labeled “AUTO/REMOTE”, “DC OFF”, and “CHARGER ONLY.” This switch should be set to “AUTO/REMOTE” to allow the inverting function to be enabled. The inverting function can then be enabled/disabled by the “12 VOLT” switch located just inside the door. Inverting is enabled when this 12V disconnect switch is “ON” and disabled when the switch is “OFF”.
If the inverting function is not needed or infrequently used, then the selector switch on the converter/inverter can be set to “CHARGER ONLY.” This setting will disable the inverting function, but it will still allow the converter to charge the batteries when 120 VAC is available. The 12 VDC wiring for the converter/inverter comes from the circuit breaker located underneath the step cover next to the house batteries. Check this circuit breaker if converter/inverter functions are not working.
The 120 VAC wiring for the converter/inverter comes from a circuit breaker in the circuit breaker box. This is the 120 VAC power into the converter/inverter. There is also 120 VAC wiring from the converter/inverter returning to a circuit breaker in the circuit breaker box. This is 120 VAC power out of the converter/inverter used to power the inverter loads. Check these circuit breakers if converter/inverter functions are not working.
There are two circuit breakers located on the converter/inverter. One of the circuit breakers is for the 12 VDC charging circuit, the other circuit breaker is for the 120 VAC output. Check these circuit breakers on the converter/inverter if there are functions not working.
Electrical Generator
The electrical generator (Figure 9-10) is located in a compartment in front of the motorhome between the chassis rails. Access to check the generator’s fluid levels can be gained by releasing the hood latches.
 Figure 9-10: Electrical generator |
Before starting or stopping the generator, make sure that all the 120 VAC appliances are turned OFF.
After the generator has been started, wait until the transfer switch has connected before turning ON any of the appliances.
The generator can be started from either the remotestart switch located on the dash or directly at the generator itself. The hour meter installed on the generator records the number of hours of operation of the generator motor—this elapsed time is needed for observing necessary maintenance schedules on the generator.
For more detailed operating instructions and to determine necessary preventive maintenance schedules and procedures, review the manufacturer’s owner’s manual.
Automatic Transfer Switch
The automatic transfer box switches 120V AC power from the shore or generator to the coach’s main distribution panel. The transfer box has a delay of around three seconds before switching power to the shore, and a delay of around 30 seconds before switching power to the generator.
If the unit is plugged into the shore but there is no power to the coach, then make sure the shore outlet has power. If power is present, this might indicate that the unit is sensing an open neutral condition. Start the generator; if the power is restored, then the shore plug or the outlet might be defective (the neutral line might be broken).
If there is no power to the coach from the shore or generator, then check the generator circuit breaker. If the circuit breakers are not tripped in the generator or the coach, the transfer box might need to be replaced. For more detailed information on the automatic transfer switch, refer to the specific owner’s instructions found in the owner’s information package.
Re-settable Ciercuit Breakers
As needed, manually reset the circuit breaker or breakers as shown in the accompanying figure. Be careful when working around these connections as an accidental, electrical short to ground (i.e., momentarily connecting the “positive” or “hot” terminal to any part of the chassis) can be hazardous and harmful.
 Figure 9-11: Circuit Breakers |
Fuse Blocks
Some of the electrical circuitry within the motorhome is protected by various fusing systems. Some of these fuse blocks are immediately accessible from the driver’s side front exterior compartment. These fuse blocks protect some of the major electrical systems of immediate concern to the driver.
Should there be any electrical failure of these components or systems, the first troubleshooting procedure should be to check the fuses and have available replacements to replace any blown fuses, as might be warranted.
The motorhome contains a computerized diagnostic center usually attached to the steering column under the dash. This center permits a computer to be connected to the on-board diagnostic center monitoring many of the operating functions and parameters of the engine so that the current operating status of the engine can be determined and any anomalies or problems might be noted. This diagnostic tool enables the motorhome owner to maintain an updated status of the engine so that the overall reliability of the motorhome can be maintained.
Seven-Pin Towing Connector
 Figure 9-12: Seven-Pin Connector |
Your motorhome is equipped with a standard, 7 pin connector near the towing hitch at the rear of the motorhome to supply the necessary circuitry to control a towed vehicle.
The wiring of that connector is shown in the accompanying diagram (Figure 9-12).
Make sure that any cable from the vehicle to be towed is wired correctly to mate properly with the connections shown in the connector. If in doubt about proper wiring, have a qualified service technician prepare and install the necessary cable to mate with the 7-pin connector on the motorhome to ensure proper operation subsequently when any vehicle is actually towed by the motorhome.
When the towed vehicle is uncoupled from the motorhome and the cable is disconnected from the 7 pin connector, be sure to close the spring-hinged cover plate on the connector to protect the contact pins from dirt or debris. In a similar manner, protect the cable end from similar damage, weather, or debris— one such method could be to place the connector end in a heavy-gauge plastic bag (e.g., polypropylene, polyethylene, etc.) and secure the bag tightly around the cable with a stout elastic band or tape and then mount the secured cable in a manner to keep it both from mechanical damage and water intrusion.
When the towed vehicle is again coupled to the motorhome through the towing hitch and the cable is again connected to the 7-pin connector, make sure the resultant connection is tight and solid so that the connection does not jar loose during use. Several supplemental methods to secure that connection have been used; some of which include securing the connection with a strong rubber band or with Velcro-type fasteners to provide a supplemental mechanical backup to the actual electromechanical connection. If a conversion adapter to convert the round, 7-pin connector to a flat, 4-pin connector is needed; purchase one from any RV after-market store.