Corvette Rear Light Modification - C3 (1969 onwards)
--- Use at your own risk! For guidance only! --This method of converting the lights to EEC standards is a little different from Ed Simmonds, in Vette News. He makes
connections in the loom inside the car, at the centre console. Using info from the AAC magazine I adapted his
instructions as I am not confident about the integrity of the wiring on my car in the centre console area, and wanted to
avoid disturbing it. I also required white reversing lamps which illuminated my "retreat", which Ed's system doesn't
allow. The principle is the same - "the choice is yours!"
Before you start ensure that you have a wiring diagram for you car, a good pair of wire strippers, lots of crimp type
connectors and a tool to close them, a drill, a circuit tester, plastic ties, some 8-10 amp "scotch lock" connectors, about
ten meters of 10 amp wire and a couple of meters of 6 amp wire. It is also a good idea to have some yellow bulbs handy
to replace the old reversing light ones. I use Humbrol yellow paint on mine, which takes an hour or so to dry. If you
have a circuit tester of the sort that has a sharp point it is always a good idea to check what each wire is doing before
you make any changes.
As They Are:
Brown
Brown
Black
(Earth)
Yellow
S/T
Black
(Earth)
Light Green
Rev
Rev
Green
S/T
Step 1.
Disconnect Battery! Remove the rear lights and take the bulb holders out of the lens assemblies. Put lens' aside.
Working on the left Stop and Tail light, cut the yellow wire, leaving enough to put a connector on each of the ends left.
Move to the left reversing lamp and cut the light green wire at a point that enables the fitting of a connector to each cut
end. Fit appropriate connectors to allow the connection of the yellow supply lead to the light green wire at the lamp end
and make the connection. (You may have to add a small length of wire if the loom prevents it stretching across.) This
has wired the indicator into the reversing lamp. Fit a connector to the light green supply wire for later connection to new
reversing lights if required.
Move to the right hand side and do the same operation, only on this side the stop and tail light wire will be dark green.
Fit the yellow bulbs in the "reversing light" holders and you can test the newly positioned indicators. Refit the reversing
light lens assemblies. Rear indicators are now complete. Remember to disconnect the battery again if you tested the
indicators.
Brown
Brown
Yellow
Connector
Green
Connectors
Yellow
Black
S/T
Rev/New Ind
Light Green
Connector
Black
Rev/New Ind
Green
S/T
Step 2.
Copyright 2004 CCCUK
May not be reproduced for commercial gain
Page 1
www.corvetteclub.org.uk
Back at the left stop and tail light, fit a connector to the end of the yellow wire left on the lamp. Move to the right S&T
lamp and do the same to the green wire left on that lamp. You will them need to connect the yellow and green lamp
wires with a length of the 10 amp wire.
The power supply will be connected to this wire later to provide brake lights. (See diagram).
10 amp wire
Brown
Connector
Yellow
Yellow
Brown
Connectors
Light Green
Black
S/T.
Green
Rev/New Ind
Connector
Green
Black
Rev/New Ind
S/T
Step 3.
Connect two lengths of 6 amp wire to the two light green supply wires and run them to the location of the new reversing
lamps (somewhere below the number plate?)
10 amp wire
Brown
Connector
Yellow
Yellow
Brown
Connectors
Light Green
Black
S/T.
Green
Rev/New Ind
Connector
Green
Black
Rev/New Ind
S/T
Light Green
Reversing Light power supply
New reversing lamp wires
New reversing lamp wires
Connectors
New Reversing
Lamps
Copyright 2004 CCCUK
May not be reproduced for commercial gain
Page 2
www.corvetteclub.org.uk
Step 4.
The brake light power wire. Remove the metal trim strip that holds the carpet under the drivers door. Lift the carpet and
locate the wiring loom guide. This runs the length of the car and you will now need to feed the 10 amp wire into it,
leaving enough at the front to connect to the brake light switch under the brake pedal and at least a couple of meters to
go "out the back" to the lights. The loom goes through the rear bulkhead behind and above the rear wheel. Take away
the carpet to follow it. I then drilled a hole on the rear bulkhead close to the original exit. Fit a grommet. The wire can
now go through that and be routed as neatly as possible to the rear lights where a "scotch lock" can be used to splice
into the wire that you fitted between the brake lights. At the brake light switch end, locate the orange and white wires
coming from the switch. The orange is the power in, the white would go via the flasher unit to the brake lights. It's
because the flasher unit has to be isolated from the brakes that we do all this!
Using a "scotch lock" connect the new 10 amp wire to the white wire near the switch. If you wish you can check the
wiring so far at this stage by connecting up the battery and pushing the brake pedal. If all is OK cut the white wire, on
the "far side" of the scotch lock of course! Replace the S&T lens assemblies. Now you should find that the brake lights
work, that the indicators flash in the reversing lights and that the brake lights do not flash when the indicators do. Put all
the carpet back and refit the retainer.
Orange
White
Old brake light power
(now cut)
Brake
Light
Switch
Scotch Lock
Scotch Lock
New power supply
to brake lights
New brake light
Circuit
Replacement Reversing Lights
The fitting of new reversing lights is a matter of choice, but as there is a handy chassis rail under the rear valence it's
pretty straight forward. The wires will be there waiting when you decide what you want. I fitted a pair of "Ring" lamps,
£2.50ish from Charlie Browns. I used a small length of steel to move them further to the front of the car, closer to the
spare wheel cover and "blacked out" the lenses a little. To the casual "passer-by" they are probably not even visible,
but still function perfectly.
The Front Lights
The arrangements here depend on what you want. I retained the original lamps as the side lights and added a couple of
the "Ring" lights, mounted behind the grill panels, as indicators. The grills are held in by screws and the original lamps
units are fitted to the grill. There are a number of metal supports behind the grill and I used these to mount the extra
lights.
However, it is possible to buy lamp holders that could be fitted into the original lamps units to allow an extra bulb, which
could be used for side or indicator. If you are fitting bulbs within the original lamps remember that the indicators need to
be yellow and 21 watts and the sides white and 12 watts. It is possible to fit a divider between the two sections, but in
fact, if the side lights are on when the indicators are used, the yellow will show "over" the white in "its" part of the lamp.
Which ever route you go, you will need a circuit tester to identify which wires you will need to relocate, as I found that
they all seemed to be the same colour! It is then just a question of moving (probably by a cut and re-fit method as the
rear) the power source for the light that you are re-locating and fitting an earth wire to one of the metal supports.
Incidentally, the side marker lamps on my car do not have bulbs in, for reasons I won't go into! However, I believe that
these flash when the indicators are on, but alternate with the lights. If yours are working, you know what I mean! I am
led to believe that this may not be acceptable to some MOT testers, but I have been unable to confirm this either way.
Copyright 2004 CCCUK
May not be reproduced for commercial gain
Page 3
www.corvetteclub.org.uk