This avoids the expense of providing a dedicated gauge or readout and also the need to provide a path through {TAIL ~ the vehicle firewall} during installation of {HEAD ~ the device} 
This avoids the expense of providing a dedicated gauge or readout and also the need to provide a path through { TAIL ~ the vehicle firewall } during installation of { HEAD ~ the device }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD