02-03-20, 09:26 PM
Good to see that grommet thinks the same way.
For the dummy-sensor, just pull the connector from the sensor (at the thermostat) and insert the leads of a wired resistor. That mimiks a certain temperature.
The sensor itself is a NTC type and changes resistance over temperature. A few values:
80° = 3700 ohm105° = 1750 ohm120° = 1150 ohm
The dashboard switches to ON below 1750 Ohm, and OFF again around 2000 ohm. There is a small hysteresis (intended).Secondly it switches ON based on a timer (1 minute?, at idle, if you once revved above 1500 rpm). Whatever condition comes first.
For repairing you could "hammer the transistor out", means there is no harm if it gets destroyed. A big blob of soldering tin above all legs and pulling out. I guess it's also glued to the pcb, might need some persuasion. Take care to leave R33 and R34 in position. A good trick is to fix them before with kapton tape, or even mask the whole surrounding. Also very helpfull in case you use a hot air gun, if available.Be carefull with the heat, the copper striped come off easily.
For the transistor replacement you could use almost any NPN transistor. BC817 is a very common type in europe.
For the dummy-sensor, just pull the connector from the sensor (at the thermostat) and insert the leads of a wired resistor. That mimiks a certain temperature.
The sensor itself is a NTC type and changes resistance over temperature. A few values:
80° = 3700 ohm105° = 1750 ohm120° = 1150 ohm
The dashboard switches to ON below 1750 Ohm, and OFF again around 2000 ohm. There is a small hysteresis (intended).Secondly it switches ON based on a timer (1 minute?, at idle, if you once revved above 1500 rpm). Whatever condition comes first.
For repairing you could "hammer the transistor out", means there is no harm if it gets destroyed. A big blob of soldering tin above all legs and pulling out. I guess it's also glued to the pcb, might need some persuasion. Take care to leave R33 and R34 in position. A good trick is to fix them before with kapton tape, or even mask the whole surrounding. Also very helpfull in case you use a hot air gun, if available.Be carefull with the heat, the copper striped come off easily.
For the transistor replacement you could use almost any NPN transistor. BC817 is a very common type in europe.