Thursday, 05 April 2007 16:14

A guide to damage analysis and repairs to satellite radio systems

Written by I-CAR Advantage Online
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 More and more vehicles on the road today are being equipped with satellite radio systems (see Figure 1). This advanced entertainment system may present new challenges when doing damage analysis and repairs.
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 Figure 1

 Figure 2

 Figure 3

 Satellite radio is commercial-free, digital radio, delivered via satellite. A service fee is required in order to receive satellite radio service. Currently there are two satellite radio service providers. Look for the Sirius® or XM® logo to help determine if a vehicle is equipped with a satellite radio system. Each company has its own service and satellites.
 Satellite radios are available as aftermarket retrofit or factory-installed systems.
 A satellite radio system uses a separate antenna. These systems may use a micro-coaxial cable (see Figure 2), which may be located under the backlite molding.
 The digital radio antenna on a 2006 Cadillac DTS is located on the roof. The antenna signal circuit is a coaxial cable that carries the radio signal information received by the antenna. The antenna cable also provides a path for DC current for powering the antenna.
Extent of damage
 Damage to a satellite radio system may include severed or pinched cables, a disconnected or damaged antenna, or damaged or missing speakers.
 If the system is factory installed, determining the extent of damage may include following a diagnostic flowchart. Following a flowchart will likely require that the vehicle be located outside with the system engaged, and a clear, unobstructed area to allow the best possible signal reception.
Replacing parts
 Satellite radio parts are replaced, not repaired. Fortunately, most parts are available separately. A severed micro-coaxial cable should not be spliced because the RF signal would be weakened.
 GM states that basecoat or clearcoat should not be applied to the digital radio antenna (see Figure 3). Doing so will damage the function of the antenna, causing poor reception or loss of signal reception.
{mospagebreak}System testing example
 An example of a procedure for testing a satellite radio is for the 2007 Cadillac STS satellite radio system. A GM Digital Radio Test Antenna (part number EL-48028) is required for the procedure.
 With the ignition off, the antenna coaxial cable is disconnected from the radio receiver. The test antenna is connected to the receiver. Next, the ignition is turned on, the radio is turned on, and the satellite radio system tuned. If there is no reception, the receiver must be replaced.
 To test the coaxial antenna cable, with the ignition off, the receiver antenna is disconnected from the coaxial cable. The resistance of the antenna coaxial cable center conductor is then tested from end to end. If the resistance is greater than 5 ohms, the antenna coaxial cable must be replaced.
 The resistance of the antenna coaxial cable outer shield is also tested from end to end. Again, if the resistance is greater than 5 ohms, the antenna coaxial cable is replaced.
 Finally, the resistance of the antenna coaxial cable is tested between the center conductor and the outer conductor. There should be infinite resistance between both conductors. If there is less than infinite resistance between the inner conductor and the outer conductor of the coaxial cable, the antenna coaxial cable is replaced. If the coaxial cable tests normal, the digital radio antenna must be replaced.
 Advanced entertainment systems such as satellite radio may present new challenges when doing collision damage analysis and repairs. Knowing how a satellite system operates can help determine the source of the problem and what steps need to be taken to return the system to satisfactory operation.

 This Advantage Online article first appeared in the I-CAR e-newsletter, which is published and distributed free of charge. I-CAR, the Inter-Industry Conference on Auto Collision Repair, is a not-for-profit international training organization that researches and develops quality technical education programs related to collision repair. To learn more about I-CAR, and to subscribe to the free e-newsletter, visit or contact I-CAR Marketing Communications Specialist Brandon Eckenrode at

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