Installing and Troubleshooting Demco Braking Systems
How to Install the Air Force One Braking System
1. Q: Is it possible for the Air Force One to drain the battery on a towed vehicle?
A: The Air Force One is a mechanically operated supplemental braking system, it uses the air from the coach to apply the brakes. Using the Air Force One will not draw power from the towed vehicle for operation. If there is a draw of power on the towed vehicle it is very possible that it will be from the vehicle itself. See the owners-manual of the towed vehicle to find out if they recommend a battery disconnect for that particular vehicle. (Some vehicles dashes light up when the brakes are applied causing a draw on the battery, or require the vehicles ignition to be in the aux position when in tow which can also cause draw on the battery)
2. Q: After installation of the Air Force One the brakes stay applied on towed vehicle when the parking brake/spring brake is released.
A: It is more than likely that the metered airline connection is tied into parking brake/spring brake airline, and that is why the brakes stay applied on the towed.
A parking brake/spring brake is released with air, so if you are tied into this line by mistake the Air Force One will be getting a full signal to apply the brakes. You will need to go back and check for the right metered airline and make the connection there.
3. Q: Why is the notification light staying on in the towed vehicle?
A: The reed switch on the back of the actuator is likely out of adjustment. Loosen the clamp and slide towards the firewall of vehicle until it goes off. Re-check calibration of the switch by depressing pedal with one hand and pulling on the back of the actuator, the light should illuminate when pulled and go off when released. If that doesn’t fix the problem re-check the wiring and make sure it has been wired correctly.
4. Q: After installing the Air Force One the check engine light came on in towed vehicle.
A: The Air Force One uses two check valves, failure to install one will cause check engine light to come on in towed vehicle. Another possible cause could be that the check valve is bad, remove check valves and blow air through each end, you should only be able to blow air one direction. If air flows in both directions replace the bad check valve. Make sure that the check valves orientations are correct. Placing the check valve in the wrong spot or direction can also cause check engine light to come on.
The Air Force One check valves should be installed accordingly: On the vehicles vacuum line running to be brake booster, install one check valve in this order- brake booster-T fitting- followed by the check valve, the black side of the check valve needs to be facing the engine. The second check valve it needs to be placed in the vacuum line coming out of the Air Force operating unit, with the black side of the check valve facing the Air Force One operating unit.
5. Q: Cable on actuator broke on towed vehicle.
A: Cable breakage can only occur if there is an improper angle or if the cable is overtightened in the anchor. The cable needs to be within 1” of a straight aligned movement of the pedal. Also the actuator needs to have 3 ½” – 4” of space between the actuator and the anchor when installed.
6. Q: After installation of the Air Force One, the breakaway pin is pulled and nothing happens.
A: The breakaway tank inside of the Air Force One operating unit does not come pre-charged. The towed vehicle will need to be hooked up to the coach and have the brakes fully applied 3-5 times to charge the breakaway tank on the operating unit. Perform this step and re-check the breakaway function.
How to Install the Stay N Play DUO Braking System
1. Q: Can the Stay N Play DUO be used on a diesel coach?
A: The Stay N Play DUO is designed for gasoline coaches with hydraulic brakes. Starting around 2003 the DOT made it mandatory for the brake lights on the coach to come on when the exhaust brake/jake brake is being used, as it is a form of braking. Since the Stay N Play DUO uses brake lights and deceleration to activate, if used on a diesel application, every time the exhaust brake/jake brake is used the brakes on the towed will activate and can cause over braking and damage to the towed vehicle.
2. Q: Turn signals are activating/pulsating the brakes on the towed vehicle.
A: The sensitivity setting on the G-Force controller is set too sensitive. Re-adjust sensitivity on a flat level surface, following the adjustment settings in the instructions.
3. Q: How do I install the LED notification light on a towed vehicle where the towed vehicle stop switch doesn’t work when towing?
A: Run an extra wire running from the red wire on the LED through the firewall to the blue wire coming out of the Stay N Play operating unit. Attach the black wire from the LED to the black wire on the G-Force controller as usual. The LED notification light will now illuminate when the unit activates.
4. Q: The owners-manual on the towed vehicle states that the battery disconnect should be on the negative side of the battery.
A: With the Stay N Play Duo you will need to install the battery disconnect on the positive side of the towed vehicles battery and install the power wire on the battery side of the disconnect. If the disconnect is installed on the negative side of the battery, the vehicle will re-ground itself to the battery through the Stay N Play DUO operating unit.
5. Q: After installation of the Stay N Play DUO the check engine light came on.
A: One of the check valves could be bad, remove the check valves and blow air through each end, it should only flow one direction. If air flows freely in each direction replace the check valve. It’s always a good idea to check the check valve before installation to make sure it’s doing its job correctly.
Look to make sure that the check valve has been installed and in the proper location/orientation. Failure to install the check valve can result in a check engine light.
It is also a good rule of thumb when installing our T and check valve to install them as close to the brake booster as possible. If there is any factory check valves in place, we then want to make sure we install them before the factory check valves on the brake booster side of the vacuum line.