Airstream INTERNATIONAL TRAILER Owner's Manual page 52

AIRSTREAM INTERNATIONAL TRAILER OWNERS MANUAL
Individual amperage draw can be measured by inserting the ammeter in the line at the magnet you want to
check. Disconnect one of the magnet lead wire connectors and attach the ammeter between the two wires.
Make sure that the wires are properly reconnected and sealed after testing is completed.
By far, the most common electrical problem is low or no voltage and amperage at the brakes. Common
causes of this condition are:
1. Poor electrical connections.
2. Open circuits.
3. Insufficient wire size.
4. Broken wires.
5. Blown fuses. (Fusing of brakes is not recommended).
6. Improperly functioning controllers or resistors.
Another common electrical problem is shorted or partially shorted circuits (indicated by abnormally high
system amperage). These are occasionally the most difficult to find. Possible causes are:
1. Shorted magnet coils.
2. Defective controllers.
3. Bare wires contacting a grounded object.
Finding the system short is a matter of isolation. If the high amperage reading drops to zero by unplugging
the trailer, then the short is in the trailer. If the amperage reading remains high with all the brake magnets
disconnected, the short is in the trailer wiring.
All electrical troubleshooting procedures should start at the controller. Most complaints regarding brake
harshness or malfunction are traceable to improperly adjusted or functioning controllers. See your
controller manufacturer's data for proper adjustment and testing procedures. If the voltage and amperage is
not satisfactory, proceed on to the connector and then to the individual magnets to isolate the problem
source. 12 volts output at the controller should equate to 10.5 volts minimum at each magnet. Nominal
system amperage at 12 volts with cold magnets, system resistor at zero and controller at maximum gain
should be as detailed in the following chart:
BRAKE SIZE
10" x 2 ¼"
12" x 2"
NOTE: THESE AMPERAGE LEVELS WILL DROP AS THE MAGNETS HEAT UP.
10" electric brakes are standard on all trailer wheels on the International Trailer Model.
AMPS/ MAGNET TWO BRAKES
3.0 6.0
3.0 6.0
D-18
FOUR BRAKES
12.0
12.0