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MAN #650519C
Cruise control operation with the GPS-50-2
While a transmission or wheel-based speed signal is ideal for operating a cruise control, the GPS-50-2 can be
used when this is not available.
If the optional remote antenna is not used, special care must be taken in selecting the mounting location for the
GPS-50-2 so that it can get a clear view of the satellites.
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The difference in mounting locations is not noticeable for a speedometer, but can affect the precision
operation of a cruise control system.
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Try to locate the GPS-50-2 as high, and close to the glass, as possible.
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It can be under a fiberglass or wood dash or in a headliner (fiberglass body).
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An unused metal speaker grill can be replaced with wood or plexiglass and the GPS-50-2 can
be mounted beneath the nonmetallic material
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Avoid having the unit surrounded by steel.
We prefer use of the optional Remote GPS antenna, part number 600041. This can connect to the OPTIONAL
ANTENNA connector on the GPS-50-2, and be used instead of the internal antenna.
The small, external antenna can then be mounted on top of the dash, to get a clear view of the satellites, while
the GPS-50-2 can remain hidden under the dash.
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The GPS-50-2 CRUISE terminal provides an ECM style speed output signal for use with cruise control
systems.
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The output frequency for the CRUISE terminal is the same as for the SPEED terminals.
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The default output of the GPS-50-2 is 8,000 pulses per mile.
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4,000 pulse per mile (square wave) is a common speed used in OEM GM cruises.
NOTE:
It is not uncommon for the raw GPS speed data to vary by as much as 6 MPH when going
under a large bridge or other (metallic) structure. The brief change of signal is usually not seen on a
speedometer, however that could fool the sensitive cruise into thinking the speed changed.
It may be possible to feel the cruise make a slight adjustment, even though your speedometer will not
show a change.
