by Rich Hirsch
If you own a car that uses a one-piece multifunction column switch that doesn't use relays to control the headlamps, the contacts in that switch suffer about a six-amp surge whenever the headlights are turned on. Over time these contacts pit and corrode and their resistance increases. With increased resistance comes heat and further deterioration. In time the contacts will fail. New column switches will become increasingly more difficult to come by and more expensive, so protecting these assemblies is worthwhile.
To protect a column switch and extend its lifetime, you can fairly easily add a relay (or relays) to decrease the current these units must carry. Adding a relay will drop the current carried by the contacts from 6 amps to ca. 0.15 amp. And in at least one case, Alfa recommends adding a relay to a column switch. Early Milanos were recalled by Alfa to add a low-beam relay to prevent switch failure at night which could leave the car without headlights.
This article describes adding two relays to the high and low beams of a '67 Duetto, but is applicable to more recent cars as well, since Alfa consistently used the same color codes for wiring their cars.
I used Hella 87106 relays since they were readily available and have mounting tabs. (There supposedly is a Hella relay that incorporates two relays into one body that may make this procedure easier, if you can find it.) The relays were mounted 1 inch apart on a 2.5" x 0.75" aluminum strip which was then secured to the chassis under the dash by the screw that holds the flasher unit to the chassis. This is close to the terminal strip on the steering column. It's advantageous to attach the relays close to the terminal strip, since the terminals can simply be unplugged from the strip and connected to the proper relay terminal. None of the original wires are cut.
1) Figure 1 shows the wiring before relay installation, Figure 2 shows the wiring after relay installation, and Figure 3 shows a relay's internal and external connections. It should help to refer to these figures while reading the instructions given below.
2) Disconnect the battery before you make any connections, since some of the wires are "hot".
3) For constructing jumper wires, use wire of sufficient girth to carry the load. OEM wire is 2.5mm and stranded--try to use a similar gauge . Also, follow Alfa's wiring color-code, if possible, i.e., use red, black, gray and green wire.
4) For maximum security don't use solderless connectors. Crimp and solder every connector. Also, most connections should be insulated with heat-shrink tubing of the proper size (obtainable from Gateway Electronics in StL). Use electrical tape if you must, but I think heat-shrink tubing is better and certainly looks neater.
5) Build the simple "wiring harness" and connect the relay assembly to it before going under the dash. You want to spend as little time as possible under the dash.
6) Optional, but recommended: Before making a connection, smear each connector with Truck-lite NYK Corrosion Preventive Compound (from Int. Auto Parts) to help exclude moisture and retard corrosion.
1) Make four jumper wires to attach the relay assembly to existing connectors:
Red jumper: FC---3"---FC---8"---FC---1"----MC
Black jumper: FC---3"---FC---3"---RC
Gray jumper: FC---8"---FC
Green jumper: FC---8"---FC
FC = female spade connector
MC = male spade connector
RC = ring connector
a) Connect one end of the gray jumper to terminal 87 of Relay 2.
b) Connect one end of the green jumper to terminal 87 of Relay 1.
c) Connect one end of the red jumper to terminal 30 of Relay 1
and the next connector to terminal 30 of Relay 2
(see Figure 2). Other connections will be made later.
d) Connect one end of the black jumper to terminal 85 of Relay 2
and the next connector to terminal 85 of Relay 1 (see Figure 2).
The ring connector will be attached later by the mounting screw
to provide circuit ground.
2) Attach the relay assembly to the body. Make sure the black jumper's ring connector is under the mounting screw.
3) Find the gray, green, and red 2.5mm wires connecting the column switch (CS) to the terminal connector (TC).
4) Disconnect the gray wire connecting the CS to the TC from the TC. Connect the wire to terminal 86 of Relay 2 and connect the TC to the gray jumper from terminal 87 of Relay 2 (see Figure 2).
5) Disconnect the green wire connecting the CS to the TC from the TC. Connect the wire to terminal 86 of Relay 1 and connect the TC to the green jumper from terminal 87 of Relay 1 (see Figure 2).
6) Danger! Remove battery terminal! Disconnect the red wire from the TC. Connect the wire to the male spade connector of the red jumper connected to terminal 30 of Relay 2. Connect the TC to the red jumper also, using the next connector (see Figure 2). Make sure these connections are well insulated (use heat-shrink tubing) and keep them away from ground sources!
7) Reconnect the battery terminal and test the headlights to make sure the wiring is correct.
