Keys to the 1986 wiring diagram:
 
Cable colour codes. You may want to study this
 L/  light (in case of light green: stabilised power)   
 B  black (ground)  G  green (hot with ignition on, fused)
 K  pink (ballast terminal to ignition distributor)  N  brown (hot all the time, unfused)
 P  purple (hot all the time, fused)  R  red (accessories fed by sidelights switch)
 S  slate (=gray)(window motors)  U  blue (from main light switch via hand/dip switches)
 W  white (hot from ignition switch or starter solenoid, eventually ending on some ballast resistor)  Y  yellow (overdrive, injection, door locks,...)
  
Relays: W1-W2 is the switching current
C1-C2 is the power (switched) current; normally open; closes by energizing W1-W2
C3-C2 is the power (switched) current; normally closed; opens by energizing W1-W2
The drawing says C1/C2 even where C3/C2-type relays
are in use. Use the proper parts numbers!

As an aid in finding the various objects in the drawing, I have added coordinate values for each one. The coordinate system has its origin in the lower left corner of the drawing, and the values are Hor/Vert percentages. E.g. 50/50 is the centre of the drawing, and 100/75 is on the right side, ¾ up from the bottom.

#Hor%/Vert% Description
1:2/86   Battery Indicator
2:9/89   Alternator
3:22/91   Steering Lock Ignition Switch
4:24/94   Connector
5:21/87   Connector
6:17/84   Connector
7:24/84   Connector
8:41/92   Red Ident
9:43/92   Ignition Switch Relay
10:10/69   Starter Motor & Solenoid Switch
11:18/69   Terminal Post
12:22/69   12 Volt Battery
13:13/62   Transmission Light-In Gear Selector
14:26/62   4 Position Lighting Switch
15:4/58   Dim/Dip Relay (UK only)
15a:4/58   Relay ??
16:13/61   Dim/Dip Fuse (UK only)
17:18/45   Power Resistor (Dim/Dip UK only)
18:11/60   Pektron Diode (Dim/Dip UK only)
19:13/55   Main Beam Warning Light
20:13/51   R.H. Headlamp Main Beam
21:13/48   R.H. Headlamp Main Beam
22:13/44   L.H. Headlamp Main Beam
23:13/41   L.H. Headlamp Main Beam
24:13/37   R.H. Headlamp Dip Beam
25:13/34   L.H. Headlamp Dip Beam
26:21/43   Fuse Unit no. 1
27:24/38   Headlamp Relay
28:26/42   Headlamp Main Beam Flash Switch (Incorporate with Indication Stick)
29:21/35   Fuse Unit no. 2
30:29/35   Fuse Unit no. 6
31:13/30   R.H. Side Lamp
32:13/26   L.H. Side Lamp
33:13/23   R.H. Tail Lamp
34:13/19   L.H. Tail Lamp
35:13/16   Number Plate Lamp
36:13/12   Panel Edge Light
37:13/8   Panel Edge Light
38:13/5   Panel Edge Light
39:13/2   Panel Light
40:21/13   Panel Light Switch
41:27/9   Panel Light
42:27/5   Panel Light
43:27/2   Panel Light
44:39/23   Sidelamp Warning Light (Italian Models only)
45:39/20   R.H. Fog Lamp (Optional)
46:39/16   L.H. Fog Lamp (Optional)
47:39/14   Heater Control Button Lights
48:39/10   Panel Light
49:39/7   Panel Light
50:39/5   Panel Light
51:39/2   Panel Light
52:44/85   Fuse Unit no. 7
53:47/85   Fuse Unit no. 5
54:33/80   Clock
55:40/80   Cigar Lighter & Switch
56:50/78   Horns
57:53/76   Horn Relay
58:56/77   Horn Push
59:56/75   Horn Slip Ring Lower Steering Column
60:33/69   Fuse
61:36/69   Fascia Radio (Optional)
62:36/64   Front Interior Light Switch
63:36/62   Front Interior Lamp
64:36/59   L.H. Front Door Switch
65:41/59   R.H. Front Door Switch
66:34/55   L.H. Rear Interior Lamp
67:41/55   R.H. Rear Interior Lamp
68:37/53   L.H. 2 Way Switch
69:41/53   R.H. 2 Way Switch
70:34/50   L.H. Door Switch
71:39/50   R.H. Door Switch
72:36/48   L.H. Courtesy Light
73:39/48   R.H. Courtesy Light
74:42/46   Rear Radio Feed
75:35/44   L.H. Cigar Lighter
76:40/44   R.H. Cigar Lighter
77:41/40   Relay (Isolation Windows)
78:36/40   Otter Switch (Thermal)
79:38/36   R.H. Front Window Lift Switch (L.H. on L.H.D.)
80:41/36   R.H. Front Window Lift Motor (L.H. on L.H.D.)
81:38/33   L.H. Front Window Lift Switch (R.H. on L.H.D.)
82:41/33   L.H. Front Window Lift Motor (R.H. on L.H.D.)
83:47/68   Otter Switch (Thermal)
84:53/68   Relay (Window Isolation)
85:57/69   To Item 100 (when have Division & no Elec Windows)
86:50/62   L.H. Front Window Lift Switch (R.H. on L.H.D.)
87:55/62   L.H. Front Window Lift Motor (R.H. on L.H.D.)
88:51/59   R.H. Rear Window Lift Switch
89:55/58   R.H. Rear Window Lift Motor
90:50/52   Front Elec. Division Window Lift Switch
91:49/42   L.H. Rear Elec. Division Window Lift Switch
92:53/42   Elec. Division Window Lift Motor
93:51/32   R.H. Rear Elec. Division Window Lift Switch
94:53/25   Division Isolation Relay
95:49/25   Otter Switch (Thermal)
96:51/18   Front Switch
97:55/18   Motor
98:51/13   L.H. Rear Switch
99:51/8   R.H. Rear Switch
100:46/28   Electric Division Only
101:61/90   Ignition Warning Light
102:63/86   Wiper Switch - Lucas No. 39944A
103:68/86   Wiper Motor 14W
104:74/85   Fuse Unit no. 8
105:75/85   Fuse Unit no. 3
106:63/77   Screen Jet Motor
107:68/76   Screen Jet Switch
108:63/73   R.H. Fuel Pump
109:63/69   L.H. Fuel Pump
110:63/66   L.H. Fuel Tank Unit
111:63/62   R.H. Fuel Tank Unit
112:70/65   Fuel Tank Changeover Switch
113:67/59   Fuel Gauge
114:64/55   Water Temperature Unit
115:67/55   Water Temperature Gauge
116:65/52   Oil Pressure Unit
117:71/52   Oil Pressure Gauge
118:64/48   L.H. Stop Lamp
119:63/45   R.H. Stop Lamp
120:73/45   Stop Lamp Switch - Hydraulic Switch in Brake Line
121:64/41   Kick Down On Gearbox
122:72/41   Kick Down Switch
123:83/93   Fuse Unit no. 4
124:85/89   Ignition Coil
125:90/84   Distributor
126:84/80   Handbrake Warning Light
127:84/76   Handbrake Warning Light Switch
128:90/76   Brake Fluid Level Switch
129:81/73   In-Line Fuse
130:82/72   Green Ident
131:82/68   Green Ident
132:83/68   Rear Window Switch
133:88/65   Relay Incorporating Resistance
134:82/65   Warning Light
135:93/73   Rear Window Heater
136:91/62   Choke Warning Light
137:93/62   Manual Choke Switch
138:97/60   Gearbox Transducer (GM400)
139:81/60   Elec. Speedometer
140:83/53   Low Coolant Warning Light
141:89/53   Low Coolant Unit
142:94/53   Coolant Sensor
143:84/48   R.H. Reverse Light
144:84/45   L.H. Reverse Light
145:84/38   Tachometer
146:71/31   Automatic Transmission and Reverse Light Switches
147:95/32   Starter Inhibit Relay
148:64/23   R.H. Heater Motor
149:64/20   L.H. Heater Motor
150:75/22   Heater Motor Switch
151:97/9   Hazard Warning System (Optional Extra)
152:84/23   In-Line Fuse
153:87/22   Hazard Flasher
154:95/22   Hazard Pilot Bulb
155:87/14   Hazard Switch
156:77/14   Flasher Unit
157:73/12   R.H. Flasher Warning Light
158:64/12   R.H. Front Flasher
159:64/9   R.H. Rear Flasher
160:64/5   L.H. Rear Flasher
161:64/2   L.H. Front Flasher
162:75/7   Flasher Switch
163:73/2   L.H. Flasher Warning Light
 
Numbers 164-185 are on the separate Airco drawing:
164    Rear Air Conditioning
165    To Ignition Switch
166    Rear Air Con Fan Relay
167    35A Fuse (50A when Refrigerated Cool Box Fitted)
168    To Socket for Refrigerated Cool Box
169    Air Con Relay
170    Speed Resistor
171    Radio Suppressors (1 micro F.)
172    Fan Motor
173    Fan Motor
174    N.S. Arm Rest
175    On/Off and 3 Speed Fan Blower Switch
176    Thermal Switch
177    Front Air Conditioning
178    To Compressor Clutch/Fan Relay
179    Compressor Clutch
180    'Pektron' Diode
181    Solenoid Valve Assembly
182    30 Amp In Line Fuse
183    Air Conditioning Unit
184    Thermostat Switch
185    Fan Motor Switch
 
Numbers 186-197 are on the separate Cooling drawing:
186    Cooling Circuit
187    Alternator Feed
188    85A Fuse
189    85A Fuse
190    O.S. Cooling Fan Relay
191    O.S. Cooling Fan
192    Link to 178
193    N.S. Cooling Fan Relay
194    N.S. Cooling Fan
195    Radiator Sensor
196    'Pektron' Diode & Radiator Sensor Relay
197    To Horn Relay Ignition Feed