With Time Delay Relay
Air Conditioner (AC) Components 1986 W/ Time Delay:
Air Conditioner (AC) Diagrams 1986 W/ Time Delay:
Locations of components
3 Earthing point
In the facia
7 Earthing point
On the radiator cross-member
20 Ignition switch
On the centre console between the front seats
22 Fuse box
In the electrical distribution box in the engine compartment, on the left-hand wheel housing
35 Selector switch for the ventilation fan
In the centre of the facia
37 Radiator fan motor (ordinary)
On the right-hand side of the radiator package
38 Recirculation valve
In the engine compartment, above the right-hand wheel housing
60 Single-pole connector
At the extreme rear of the engine compartment, at the compressor
67 6-pole connector
In the engine compartment, at the extreme rear on the right-hand side, at the air intake
59 2-pole connector
One adjacent to radiator fan 37
One adjacent to AC radiator fan 172
74 Resistor for ventilation fan accessible
Under the left-hand speaker grille
142 Solenoid valve for raising the idling speed, AC
On the engine, on the by-pass hose of the throttle housing
143 Recirculation switch, AC
In the centre of the facia
149 Main switch for ventilation fan
On the facia, in the air distribution control (upper contact)
150 Air distribution switch, AC position
On the facia, in the air distribution control (lower contact)
152A 29-pole white connector
152B 29-pole red connector
152C 29-pole black connector
In the electrical distribution box in the engine compartment, on the left-hand wheel housing. The connectors are accessible from the interior of the car.
155 Relay for the AC radiator fan
In the electrical distribution box in the engine compartment, on the left-hand wheel housing
156 Relay for the AC compressor
In the electrical distribution box in the engine compartment, on the left-hand wheel housing
158 Negative distribution terminal
In the electrical distribution box in the engine compartment, on the left-hand wheel housing
166 Pressure switch for the AC radiator fan
In the engine compartment, on the drying agent container, forward of the right-hand wheel housing
168 Coolant temperature switch, AC
On the radiator inlet hose, near the distributor
169 Switch, AC
In the centre of the facia
170 Compressor for the AC
At the rear of the engine compartment
171 Anti-freeze thermostat (cycling clutch contact) for the AC
In the engine compartment, on the right-hand side of the air conditioner housing
172 Radiator fan for the AC
On the left-hand side of the radiator package
173 Diode for the AC compressor
In the cable harness, at the rear of the valve cover
200 Control unit for the fuel injection system
Forward of the right-hand front door, below the facia on the left-hand side (behind the trim)
201 Engine earthing point
at the engine lifting lug
203 Throttle angle transmitter - fuel injection system
On the throttle housing
Operation
Certain cars are equipped with an Air Conditioner (AC). This section covers the 1986 models for the U.S.A., Canadian, Japanese and Australian markets only.
Compressor and radiator fan motor 37
The AC can be switched on and off by means of AC switch 169, which is supplied from fuse 6, via the 29-pole black connector 152C. When the switch is depressed, the lamp built into the button will be supplied directly (not via the resistor), so it will light up with full intensity. (When the switch is not activated, the lamp is supplied from the instrument lighting rheostat.)
Compressor 170 and ordinary radiator fan 37 are connected via relay 156, whose contacts are supplied from fuse 25. The relay will be energized when the following conditions are satisfied:
Pressure switch 166 is closed, i.e. the refrigerant pressure is at least 2.8 bar.
Anti-freeze thermostat (cycling clutch contact) 171 is closed, i.e. the ambient temperature is at least about +6 °C.
When the relay is energized, the compressor will be supplied only if temperature switch 168 is closed. (The switch will open if the engine temperature exceeds around +115 °C.)
Diode 173, which is connected in parallel with the compressor, reduces the voltage transients at the instant when the compressor is switched off.
Delayed connection when starting
Relay 156 is equipped with two time delay functions. One of them is activated whenever the engine is being started. Ignition switch 20 (in the start position) supplies pin 50, and if switch 169 is then depressed, the energizing of the relay and thus starting of the compressor will be delayed for around 10 seconds, to avoid an excessive load on the battery.
Idling speed compensation and cut-out at full load
There are two systems, i.e. one for cars equipped with the 16-valve engine and the other for cars with the 8-valve engine.
On cars with the 16-valve engine, idling speed adjustment motor 272, which is controlled by control unit 200 for the fuel injection system, is used for idling speed compensation. To prevent the engine speed from falling when the compressor is started at engine idling speed, the energizing of the relay electronics is delayed, to give the control unit time to adjust the idling speed.
The control unit receives a signal via relay pin 16 when the time delay of the relay is activated, and it then starts idling speed compensation. After 0.6 seconds, the relay will be energized and the compressor will start. The relay electronics are supplied (in the drive position) via pin 15.
When the engine is being run at full throttle, pin TK of the relay is earthed through throttle angle transmitter 203, and the relay trips the compressor.
On cars with the 8-valve engine, solenoid valve 142, which is always open when the compressor is running, is used for idling speed compensation.
When the engine is being run at full throttle (butterfly valve open more than 700), pin TK of the relay is earthed through throttle angle transmitter 203, and the relay trips the compressor.
AC radiator fan 172
Extra radiator fan 172 for the AC is connected via relay 155 and is supplied from fuse 6.
The relay coil is supplied from the contacts of relay 156 and from pressure switch 166. The AC radiator fan thus runs when AC switch 169 is depressed and pressure switch 166 is closed.
Recirculation valve
Recirculation valve 38, which controls the recirculation damper, will be switched on when recirculation switch 143 is depressed. The switch is supplied from fuse 6. When the switch is depressed, the lamp built into the switch will light up with full intensity.
The recirculation valve is also connected across main switch 149, when the air distribution control is in position 0 or 4 (regardless of the position of switch 143). The supply is taken from fuse 9, via ventilation fan resistor 74.
Fault-tracing hints
As a general rule, the supply to the unit is live when the ignition switch is in the drive position. If none of the components are faulty, check the cable harnesses, connectors and earth connections.
Compressor and radiator fan motor 37
1. Check fuses 6 and 25 and check that the supplies to AC switch 169 and relay 156 are live.
2. Press the AC switch. Measure the voltage across pressure switch 166 (the pressure switch should be closed). Note that refrigerant will spray out when the pressure switch is disconnected. Caution: Risk of frostbite.
3. Check cycling clutch contact 171. (It should close at +6 °C.)
4. Check that the relay is energized and that the relay contacts (87 and 87A) are live. If not, check that the coil electronics are being supplied from thermostat 171 and from the + 15 distribution terminal. When the relay is energized. terminal 16 should be live. At full throttle, terminal TK should be earthed.
5. Check that the supplies to the compressor and the radiator fan are live. (Temperature switch 168 should be closed.)
AC radiator fan 172
1. Check fuse 6 and check that the supply to the AC switch and to relay 155 is live.
2. Press the AC switch. Measure the voltage across pressure switch 166 (the pressure switch should be closed). Note that refrigerant will spray out when the pressure switch is disconnected. Caution: Risk of frostbite.
3. Check that relay 155 is being energized and that the supply to the AC radiator fan is live.
Recirculation
1. Check fuse 6 and check that the supply to recirculation switch 143 is live.
2. Press the switch and check that the recirculation valve is activated.
3. Check fuse 9 and check that the supply to main switch 149 in the air distribution control is live.
4. When the control is in position 0 or <- ->, the recirculation valve should be activated.