5.6. Check, removal and installation to the place of electric switches of the cooling system

Thermostatic switch of the electric fan of the cooling system

Check

The procedure of check of the switch is described in the Section Check, removal and installation to the place of the electric fan of the cooling system as a part of the procedure of check of the fan.

Removal

 PERFORMANCE ORDER

1. The switch is located in the lower part of the right tank of a radiator. Before starting removal of the switch, it is necessary to cool the engine and a radiator.

2. Merge the cooling system (see the Head Routine maintenance). Alternatively - prepare the corresponding plug for a switch opening blockage in a radiator. In case of application of the last method be extremely careful do not damage a radiator, also do not allow hit in a radiator of foreign particles and materials.
3. Disconnect the plug from the switch.
4. Carefully unscrew the switch from a radiator. In case draining of a cooler, then, in order to avoid its flood was not made, stop up a switch opening.

Installation into place

Carefully clear a switch carving, then install the switch into place, working as it should be the return to a removal order. Make sure that the switch is tightened hardly, then again fill in the cooling system (see the Head Routine maintenance)

In conclusion start the engine and warm up it up to the normal working temperatures. Without switching off the engine, make sure that the switch joins and switched off in the necessary timepoints.

Cooler temperature measuring instrument sensor

Check

 PERFORMANCE ORDER

1. The sensor is located in the left part of a head of cylinders, in the same place, where also the thermostat.
2. Food moves on temperature measuring instrument via the switch (ignition key) and a safety lock. The sensor is installed in a chain of grounding of the measuring instrument. A basic element of the sensor is the thermistor - an element which resistance decreases in a certain dependence at temperature increase. While a cooler cold, resistance of the sensor is big, electric current via the measuring instrument is small and the arrow of the measuring instrument is in a blue (cold) part of a scale. In process of temperature increase of a cooler resistance of the sensor falls, current increases and the arrow of the sensor moves towards the upper edge of a scale. In case the sensor is faulty, it has to be replaced.
3. In case of failure detection of the measuring instrument first of all check functioning of other devices; if other devices also do not work, check electric food of an instrument guard. If indications of the measuring instrument are not stable, malfunction can be in the voltage stabilizer which in this case has to be replaced (the stabilizer is an integral part of a payment of an instrument guard (see the Head Sistem of electric equipment). In case there is a malfunction only of temperature measuring instrument, make check as follows.
4. The arrow of the indicator of temperature remains in the cold sector of a scale at the hot engine. Disconnect the plug of the sensor and ground the corresponding wire on a head of cylinders. If now at inclusion of ignition of the shooter of the indicator deviates, then the sensor is faulty - it has to be replaced. If the arrow still does not move, remove an instrument guard (The head Sistema of electric equipment) and check conductivity of a contour between the block of the sensor and the measuring instrument, and also power supply of the block of the measuring instrument. In case there is no break of a contour, then the measuring instrument which has to be replaced is faulty.
5. If the arrow of the sensor remains in a hot part of a scale of the indicator at the cold engine, disconnect a sensor wire. If now the arrow comes back to a cold part of a scale, then the block of the sensor is faulty and has to be replaced. If the arrow still remains motionless, check other part of a contour as it is described above.

Removal and installation into place

The same procedure, as described above in the Section on the thermostatic switch of the electric fan of the cooling system however check and if necessary replace copper sealing washers. On some models access to the switch is complicated and for its providing removal of other components can be required (or movings towards hoses, wires and so forth).

Sensor of temperature of a cooler of system of injection of fuel (Bosch LH-Jetronic)

Check

 PERFORMANCE ORDER

1. The sensor of temperature of a cooler is screwed in in a flange of the inlet pipeline in a back part of a head of cylinders.
2. The sensor is a thermistor (see §9) . The block of the electronic actuation device of system of injection of fuel gives food on the sensor and by measurement of size of current in a contour of the sensor determines temperature in the engine. Then, the obtained information in total with other data, is exposed to the corresponding processing and influences duration of opening of injectors.
3. In case of malfunction of a contour of the sensor or issue of the wrong information to them the system of feedback of the electronic actuation device (ECU) will consider temperature of the engine of equal 20 °C. At the same time the system of injection of fuel will continue to work without changes with the lowered efficiency. At the same time the alarm lamp of the engine on the device a guard lights up. For correction of malfunction it is necessary to address to representative office of Saab.
4. For check of the sensor disconnect the plug from the electronic actuation device of injection of fuel (ECU) (see the Head Toplivnaya and exhaust systems), then connect to the 2nd (yellow) plug and the 11th (black) an ohmmeter and measure sensor resistance, having compared it to the value given in Specifications.
5. If resistance is higher than demanded, disconnect the plug from the sensor and by means of an ohmmeter measure resistance of the sensor. If now value equally demanded, then it is necessary to assume malfunction of a contour or corrosion of plugs. In case the measured size of resistance is not right, it is necessary to replace the resistor. After check of wires and the resistor connect wires to the electronic actuation device (ECU) and the sensor again.

Removal and installation into place

The same procedure, as described above in this Section for the thermostatic switch of the electric fan of the cooling system. On some models access to the switch is complicated and work with the sensor requires removal of other components (moving towards hoses, wires and so forth).

Sensor of temperature of a cooler of system of injection of fuel (Trionic)

Check

The sensor of temperature of a cooler is screwed in in the inlet pipeline of a back part of a head of cylinders. On models with usual absorption access to the sensor opens by removal of the top part of the inlet pipeline (see the Head Toplivnaya and exhaust systems)

The sensor functions in the same way, as well as the sensor of system of injection of LH-Jetronic fuel (see §§15 and 16)

 PERFORMANCE ORDER

1. For check of the sensor disconnect from it the plug and use an ohmmeter for measurement resistance of an internal contour. If necessary the sensor can be removed and heated-up in a pan with water. Resistance has to equal to the value given in Specifications.
2. If resistance is higher demanded, then there is either a malfunction of a contour, or corrosion of plugs. After check of wires install the sensor (if he acted) and connect wires.

Removal and installation into place

The procedure is similar to the procedure described above in this Section for the thermostatic switch of the electric fan of the cooling system.