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How the Temperature Gauge Circuit Works for Petrol Vehicles

Model: (Various brands) Various
Part: Checks and maintenance

Video tutorial
Detailed instructions - The following describes the operation of the classic water/oil thermometer circuit on a vehicle with analogue instrumentation. The diagram shows a simplified circuit: the battery provides the starting 12V, the ignition key powers the circuit when the key is inserted, while the fuse protects the circuit. The analogue gauge on the dashboard is a galvanometer. The sensor (screwed into the engine) is a 'variable resistor' known as NTC, while the term 'body' refers to the ground, which is the return path for the current to the chassis. The key lies in the temperature sensor, which is an NTC, meaning Negative Temperature Coefficient; a resistor that changes value based on temperature.

Posted on 30 September 2026 by ScegliAuto


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How to Replace the Front Indicator Bulb on a Citroen C4 Picasso

Follow the procedure to remove and replace the front indicator bulb of the Citroen C4 Picasso and Grand Picasso. First, open the bonnet of the vehicle and disconnect the connector along with the bulb holder of the indicator light. Then, remove the small bulb of the indicator and replace it with a new one, as shown in the video. At this point, refit the bulb and the bulb holder onto the front optical unit, replacing the other indicator in the same manner.

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by ScegliAuto

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