| Author | Message | ||
     Daniel Diewerge Experienced User Username: didi13109 Post Number: 39 Registered: 11-2009 |
The automatic temperature control in my 1985 Bentley 8 is giving me headaches…literally. From one moment to the other, the system switched permanently to the “Fascia” and “recirculation” modus and keeps blowing stale lukewarm air only. Fan speed can be selected but even in the defrost modus; air is only coming from the Fascia vents. When switching the system on and of, there is no actuator motor activity. To narrow down the problem, I replaced the two circuit boards and all the actuator motors with no effect. I suspect that I must have a problem with the upper sensor chain since disconnecting the main sensor chain plug at the servo box plug closes the “Fascia” vents and opens the recirculation flaps. I tried to measure the resistance in the sensor chain to compare it to the temperature/ resistance chart in the manual and it is here where I could use an advice from an electronic expert. When connecting a circuit analyser to the sensor chain plug and a ground, no stable value can be measured. As a complete electronics amateur (or lets better say dilettante) I can only suspect that the current of my measuring tool somehow affects the thermistors in the chain while measuring. On the other hand, I simply cannot find the temperature sensor that, according to the manual, is supposed to be mounted in the boot on the right hand side. Any help would be truly appreciated Daniel | ||
| Paul Yorke Grand Master Username: paul_yorke Post Number: 1190 Registered: 6-2006 |
Hi Daniel, I think you are supposed to measure the resistance across the two chain connections. (possibly add a voltage to one side and measure the voltage coming out the other side, but I don't think so. No manual to hand) I think by your year the sensor had been moved from the boot to the front of the car. If in the boot. It should poke out behind the right hand rear bumper. Look for a hole and rubber grommet. Often when paintwork is done, it is pushed inside and forgotten about. It then registers the heat from the exhaust near the boot floor. Make sure that the facia micro switch inside the dash is operated by the facia linkage as it goes around. |
