| Subject: | Radio Telephone/Mobile Radio (Transceiver) Installation and Troubleshooting
Guidelines |
| Models: | 1990-2005 Passenger Cars and Trucks |
This bulletin is being updated to add models, model years and revise the information.
Please discard Corporate Bulletin Number 83-96-05 (Section 9 - Accessories).
The following information is being provided to assist in the installation and
troubleshooting of radio telephone/mobile radios.
Certain radio telephones or land mobile radios also known as radio transceivers),
or the way in which they are installed, may adversely affect various vehicle operations
such as engine performance, driver information, entertainment and electrical systems.
Expenses incurred to protect the vehicle systems from any adverse effects of
any such installation are not the responsibility of General Motors Corporation.
The following are general guidelines for installing a radio transceiver in General
Motors vehicles. These guidelines are intended to supplement, but not to be used in
place of, detailed instructions which are the sole responsibility of the manufacturer
of the involved radio transceiver. Although this document refers to passenger vehicles,
the same general guidelines apply to trucks.
Important: Refer to the illustrations found later in
this bulletin for aid in installation.
| - | Locate transceiver for remote radios on driver’s side of trunk as
near to the vehicle body side as possible. |
| - | One piece transceivers should be mounted under the dash or on transmission
hump where they will not interfere with vehicle controls or passenger movement. |
| - | Great care should be taken not to mount any transceivers, microphones,
speakers or any other item in the deployment path of a Supplemental Inflatable Restraint
(air bag). |
| - | Each vehicle model and body style reacts to radio frequency energy differently.
When dealing with an unfamiliar vehicle, it is suggested that a magnetic-mount antenna
be used to check the proposed antenna location for unwanted effects on the vehicle.
Antenna location is a major factor in these effects. |
| - | The antenna should be a permanent-mount type located in the center of
the roof or center of the rear deck lid. Glass mounted antennas should be kept as
high as possible in the center of the rear window or windshield. If a magnet-mount
antenna is used, care should be taken to mount the antenna in the same location as
a permanent-mount type. If a disguise-mount antenna is used, great care should be
taken to shield any tuning network from vehicle electronics and wiring, or to mount
the tuning network in an area completely clear of vehicle electronics and wiring. |
| - | Standard metal mount antennas may be mounted on a vehicle with nonmetallic
body panels by two methods. Most nonmetallic skinned vehicles have metal frames
underneath. Mounting the antenna near a metal frame section and bonding the antenna
mount to the frame with a short metal strap will provide the groundplane connection.
Some antenna manufacturers offer "groundplane kits" that consist of self-adhesive
metal foil that may be attached to the body panel to provide the groundplane for the
antenna. |
| - | Some vehicles use glass that contains a thin metallic layer for defrosting
or to control solar gain. Glass mount antennas will NOT function when mounted on
this type of glass. |
| - | If RF-related interactions occur when using a hitch or bumper-mount HF
antenna on a vehicle that has body on frame construction (i.e. pickup, SUV) connect
a ground strap from the vehicle frame to the bottom rear of the vehicle body (for
station wagon type vehicles), or from the vehicle frame to the bottom rear of the
cab (pickup style vehicles). |
| - | Always use a high quality coax (at least 95% shield coverage) located
away from the engine control module (ECM) and other electronic modules. |
| - | Care should be taken to maintain as great a distance as possible between
any vehicle wiring and the feedline. |
| | It is important that the antenna be tuned properly
and reflected power be kept to less than 10% (VSWR less than 2:1). |
| • | Radio Wiring and Connection Locations |
| - | Connecting radio power on General Motors vehicles is model dependent.
The installer must decide which one of the following four methods will be appropriate. |
| • | Connect the positive and negative leads directly to the battery terminals
(illustrated in this guideline). |
| • | Connect the positive lead to the auxiliary power terminal (located at
the underhood fuse center or identified by a red plastic cover in the underhood area)
and connect the negative lead directly to the negative battery terminal. |
| • | Connect the positive lead to the auxiliary power terminal and connect
the negative lead to the battery body connection point (identified by a short #10
AWG or larger wire running from the negative battery terminal to the body of the vehicle). |
| • | Connect the positive and negative leads to the Special Equipment Option
(SEO) wiring provided for this purpose. |
| - | If connections are made directly to the battery terminals, the GM-approved
methods of connecting auxiliary wiring include the adapter package illustrated in
Figure 2, NAPA-Belden replacement battery bolts, P/N 728198, or
drilling and tapping the hex end of the original battery bolts 10-32 X 3/8"
deep. Note that it is recommended that a fuse be placed in the transceiver negative
lead to prevent possible transceiver damage in the event the battery-to-engine block
ground lead is inadvertently disconnected. |
| - | For ONE-PIECE TRANSCEIVERS where ignition switch control is desired and
no SEO wiring exists, a 12 volt power contactor must be installed in the transceiver
positive lead. The contactor should be located near a proper 12 volt feed.
The coil of the contactor should be connected through an appropriate in-line fuse
to an available accessory circuit or ignition circuit not powered during cranking.
The contactor coil must return to a proper negative point. The detailed view in
Figure 1B illustrates direct connection to the vehicle battery. |
| - | Any negative lead from a handset or control unit must return to a proper
negative connection point. It is preferable that the positive lead for a handset
or control unit be connected directly to a proper positive feed. If ignition switch
control is desired, the handset or control unit positive lead may be connected through
an appropriate in-line fuse to an available accessory circuit or ignition circuit
not powered during cranking. It is recommended that the handset or control unit positive
and negative leads be appropriately fused separately from the transceiver positive
and negative leads. |
| - | If multiple transceivers or receivers are to be installed in the vehicle,
power leads to the trunk or under dash should be connected to covered, insulated terminal
strips. All transceivers or receivers may then have their power leads connected to
the strips. This makes a neater installation and reduces the number of wires running
to the vehicle underhood area. |
| - | The power leads should be brought through a grommeted hole in the front
bulkhead that must be provided by the installer. For trunk-mounted transceivers,
the cables should continue on along the driver’s side door sills, under the
rear seat, and into the trunk through the rear bulkhead. All attempts should be made
to maintain as great a distance as possible between radio power leads and vehicle
electronic modules and wiring. |
| - | If the battery is located on the passenger side, radio power leads should
cross the vehicle in front of the engine. |
| - | Should vehicle-radio interaction develop following installation, the source
of the problem should be determined prior to further operation of the vehicle. Most
interaction problems can be eliminated by following the installation guidelines. |
| - | If any vehicle-radio interaction problems exist after following these
guidelines, refer to the EMC Troubleshooting Chart at the end of this bulletin. |
Figure 1A -- Transceiver Installation -
Example of Remote Mounted Transceiver
