TK 56430-18-IP-EN
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Ground Strap Installation
Every Vehicle Powered truck unit comes with a compressor ground strap kit. This ground strap ensures that the Thermo
King compressor is properly grounded and will received adequate voltage. If the ground strap is not used, the
compressor will be grounded through the vehicle’s engine block which could result in electrical resistance and
decreased voltage. Decreased voltage to the compressor will result in the compressor clutch not fully engaging,
increased current and higher temperatures which in turn lead to excess clutch wear and premature clutch failure.
Mount one end of the chassis ground wire to either the firewall of the engine compartment (as shown in photo) or
directly to the vehicle frame. The mounting location on the firewall or frame must be free of paint to ensure a good
electrical connection. Remove enough paint until bare metal is showing and so the entire area of the ground strap ring
terminal is touching bare metal. The compressor ground strap may share a fastener with an OEM ground strap. Use an
ohmmeter to check the resistance of the ground circuit. Hold one probe of the ohmmeter to an unpainted area on the
frame or chassis and hold the other probe onto the loose end of the chassis ground strap. If the resistance is greater
than 0.1 ohms, the connection needs to be improved. Once a good ground is established, cover the interface between
the chassis and the ring terminal with dielectric grease to minimize corrosion and verify a good electrical connection.
Figure 27.
Typical ground strap shown installed on vehicle’s firewall.
Mount the compressor to the drive kit per the drive kit instructions. Fasten the other end of the chassis ground wire to
one of the open mounting holes on the compressor ears (if ear mount style – shown in first photo below) or under one
of the compressor mounting bolts (if direct mount style – shown in second photo below.) Cover the interface between
the compressor body and the ring terminal with dielectric grease to minimize corrosion and verify a good electrical
connection.
Ground Strap shown installed on ear mount style and direct mount style compressors.
