| Author | Message | ||
     Brian Vogel Grand Master Username: guyslp Post Number: 494 Registered: 6-2009 |
Hello All, While I had the top roll off and was working on other "things electronic" I decided to pop out the climate control temperature sensor that's located between those two small plastic grates at the center and take some photos.   While I'm not having issues with the climate control, I am curious as to what this thing is composed of and how it works. It appears to be two simple electronic components mounted to a non-conductive board of some sort. That board is then riveted to a metal bracket that's used to hold it in place. There is a single wire going to one leg of each of the two respective components. The remaining legs on each are connected together. I presume the whole purpose of the third leg that results from this being sheathed and mounted to the board is to prevent rattle. If anyone knows what the components are, how they work together, and, for the sake of future diagnosticians, how one would go about checking whether this thing functions I would appreciate it. Brian, always curious | ||
| Jan Forrest Grand Master Username: got_one Post Number: 486 Registered: 1-2008 |
I would say that the circular component will be a thermistor - a resistor that varies value according to ambient temperature. The other is a simple resistor to add a fixed bias to the range of the thermistor. Unfortunately without a component ID it's impossible to do more than guess the temperature range versus resistance change. It can be easily if crudely checked out with a resistance meter securely clipped onto the leads followed by dipping just the sealed thermistor into cups of water at various temperatures checked with a brewing thermometer. | ||
| Paul Yorke Grand Master Username: paul_yorke Post Number: 1062 Registered: 6-2006 |
A thermister and a resistor in series - in a chain. Don't dunk in water, just hold the thermister in your fingers and see the resistance change. I think the aircon manual gives a graph of resistance v temperature if you wish to pursue it further. | ||
| Brian Vogel Grand Master Username: guyslp Post Number: 497 Registered: 6-2009 |
Thanks gentlemen. At this point the thing is back in the top roll and the top roll is back in the car. I was really just curious about this item and whether anyone had ever needed to replace or repair one. It certainly wouldn't be a challenge to repair if one knew exactly what the characteristics of each component were intended to be. Brian | ||
| Richard Treacy Grand Master Username: richard_treacy Post Number: 2853 Registered: 4-2003 |
Note PY's warning. Also, unlike the thermistors of the engine temperature gauge, utter rubbish on these cars after a year or so unless modified by the way, the ones on the climate control seem to last forever. If it has continuity, maybe 3K, and the system functions, leave well alone. The component drift is so small that an ageing thermistor will correlate with just a millimetre or so on the temperature selector dial. RT. |
