Wiring
Installation:
Running Extra Cabling Through the
Firewall
(Range Rover 4.0/4.6)
Introduction
Getting the Cables through the Firewall
Auxiliary Fuse Box Installation
Introduction
Installation of many additional equipment items such as trailer brake
controllers, CB antennae, etc often requires additional wiring to be
run through the firewall/engine bulkhead. On the Classic this was
seldom much of a problem due to the rather casual sealing of the
firewall and abundance of holes in it. On the 4.0/4.6 the task is
considerably more difficult as all cables and pipes going through the
firewall are tightly sealed as well as being buried in deep layers of
insulating foam. On this page, Ron Beckett kindly shares
his method of running the extra cabling he needed on his Right Hand
Drive 4.6 when he installed his CB, auxiliary cigarette lighter
sockets, dual battery controller, and LED monitors for his EAS pump and
brake pump (these upgrades are depicted in the photo at the top of this
page and described in more detail on the CB installation page). To top off
his installation, Ron also describes the addition of an auxiliary
fusebox which provides power to all these accessories.
Getting the Cables through the Firewall
To get all these wires through the firewall, Ron ran a length of
multi-core trailer wiring into the cab via the grommet behind the
cooling system expansion tank. He ran the CB antenna coax the same way
(see photos below). To reduce friction when sliding the cables through
(and prevent the grommet being pulled out of the firewall), lubricate
the cables with a small amount of liquid kitchen detergent and water.
(Note -- the extra two white wires in Ron's photos below were only
temporary for another job he was doing).
When the tank is lifted out of the way on RHD models (it
just clips
in), carefully remove the clips holding the insulation in place.
This
will give access to the grommet. On a LHD car, you can probably
also
access the matching grommet on the LH side. When you look up under
the dash (left hand photo) you can see where the wiring loom comes
through that
grommet. Because Ron knew what was behind the grommet (from
looking at a wrecked car), he was able to run an electric drill (not
for the faint-hearted!) through the grommet which has an odd-shape and
thus has a place where one can drill it.)
Auxiliary Fuse Box Installation
Ron also added an auxiliary fusebox to supply all the new accessories;
he found a long narrow unit that fitted nicely in the space between the
coolant expansion tank and the side of the engine bay (see photos
below). This location is handy to the battery to ease tapping into it.
