Thanks
to the efforts of Erich Bozzer and his article
from the Boss 302 Registry here, the
procedure is very straightforward and easy to
accomplish. It is highly recommended that you
read the article and it's step by step outline.
The schematic shown below is meant to provide you
with a layout of the pins and wiring before and
after the procedure. The pinouts from a non tach
car are in a different order, along with a few
wiring differences, than the tach car connector.
The pins from the connector are removed with a
small paper clip inserted into each pin from the
front of the connector and depressing the small
clip or tang that holds the pin in it's location.
These modifications will allow you to use a tach
cluster with a non tach car.
There are some important results that you need to
be aware of.
1. The oil pressure gauge becomes a warning
light, therefore you need to change the larger
bell shaped oil sending unit with the smaller
sending unit used for a warning light.
2. Your three wire engine gauge feed wiring
harness for the coil, temp and oil gauges may
need to be modified. Remove that harness and
check the resistance of the center wire, the oil
sending unit. If it shows 0 ohms, then you can
reconnect it and use it. If it shows 5 ohms, you
need to replace the harness with one that reads 0
ohms or untape the harness, bypass the wire with
a new wire and tape up the harness.
2. Your ammeter is no longer used and charge
indication will have to accomplished by other
means. There are important differences in the
wiring harnesses between using a warning light or
an ammeter. You can use a separate add on voltage
gauge if you want to.
Before you perform this modification, you will
need to disconnect the battery, remove the
dashpad as outlined at Dash Pad Removal, then remove the instrument cluster as
outlined at Instrument Cluster. When you look at the connector, you
will see the pin locations numbered. |
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