Electrical Testing
A digital multimeter is a useful tool for troubleshooting and isolating electrical related problems. Open
circuits are identified by no continuity shown on the display (1OL). Open circuits in the SAMS manifold
electrical system are typically caused by pins that have pulled loose from the associated harness
connector, wires that are broken at the pins in the harness connector, breaks in the coil windings, or
broken wires in the wiring harness due to improper harness routing during the installation of the system.
The coil can be tested for an “open” or “short” circuit by checking the resistance value of the windings.
The coil must first be isolated by disconnecting its associated wiring harness connector. Obtain a
multimeter as previously suggested and rotate the dial to the OHMS (resistance) setting. In most cases,
this should turn on the power to the multimeter. If not, turn on the required switch to power the
multimeter. Connect the
red
lead of the multimeter to the
red
lead in the wiring harness connector of the
coil to be tested. Next, connect the
black
lead of the multimeter to the
black
lead in the wiring harness
connector of the coil to be tested. The display on the multimeter should read approximately 8 to 10 ohms
of resistance. If the display of the multimeter shows zero ohms of resistance, the coil is “shorted” and
requires replacement. If the display shows an “open” circuit, as indicated by displaying “1OL”, the coil
requires replacement, as well.
Note:
Prior to disconnecting the manifold wiring harness to perform the continuity check, be sure power
has been removed from the SAMS system ECU. This can be accomplished by disconnecting the white
wiring harness connector in the vicinity of the manifold assembly. This prevents the SAMS system from
operating when the engine is not running, which could result in unanticipated suspension movement.
The SAMS system requires 12VDC for proper system operation. The ECU uses the 12VDC supplied by
a user defined vehicle power source to control the manifold valve coils and also uses the voltage to create
an internal 5VDC reference signal. This lower voltage provides feedback to the ECU from the system
sensors to detect and maintain the vehicle ride height. Therefore, if the supply voltage is either
excessively low (typically less than 9.7VDC) or excessively high (typically 14.8 VDC or above) system
performance can be adversely affected.
The multimeter, using the DC voltage scale, is also a useful tool in checking and verifying the correct
supply voltage and that a good system and manifold ground is present. The system ground and manifold
ground are provided through separate ground wires. Refer to the SAMS wiring diagrams to determine the
power and ground wires associated with the system.
Note: DC voltage is polarity sensitive. Therefore the multimeter
red
lead should be connected to positive
(system power: 12VDC) and the black lead connected to negative (system ground).
See the following pages for samples of the SAMS system schematics.
