treadshuffle
New Member
- Posts
- 2
Summer is approaching fast, and I'm itching to get the aircon working on my Freeby. But I had some questions beforehand. Some wiring diagrams seem to omit my primary suspect, the Evaporator Temperature Sensor. I could swear I've seen one with a direct connection to the MEMS3 and not the instrument pack, Rave currently shows the TD4 and NAS as having it connected to the instrument pack. For the K-series, I could only find this;
Which seems to be the power distribution (?) centre taps for the sensor, unless its showing the 'harness' as a single line, that actually seems to make more sense. Anyway, as soon as I read the A/C logic in the workshop manual, I knew this is the exact kind of fix I'd been dreaming about. Simple, cheap and often-overlooked. I've had the A/C recharged, it seems to hold the pressure well, no odd noises from the compressor, except that the clutch doesn't engage/doesn't stay engaged for more than 10 seconds after starting the engine, maybe less. It's either this, the pressure sensor, or the thermostatic expansion valve (I have no idea what this is or does), or the compressor clutch, or the compressor itself, easy-peasy. I'm leaning on the evap sensor because it seems the most likely, considering one of the failure modes (open circuit) would present these symptoms.
Symptoms:
-A/C light turns on, so that's a good sign
-No cold air whatsoever
-Compressor momentarily engages and disengages
Questions:
1) I read that the Evap Temp Sensor is an NTC thermistor with 5.3kΩ at 22°C, does anyone know another temperature-resistance value pair so I can match it to an off-the-shelf one? (I don't want to pay ~£130 for this beauty right here) (It looks like a sensor bulb)
I'm not even sure if this is the right part because I found something called the evaporator thermostat (?)
With absolutely no reference to it in the Rave manuals.
2) Do I have to remove the whole fascia to change the sensor/thermostat/mystery temperature thingy?
3) Can I just glue/affix with a thermal pad the 'appropriate' thermistor on the evaporator in its original position and hope that it will work?
4) Any details about the A/C logic, to clarify the hysteresis (?) in the engaging/disengaging of the compressor?
Which seems to be the power distribution (?) centre taps for the sensor, unless its showing the 'harness' as a single line, that actually seems to make more sense. Anyway, as soon as I read the A/C logic in the workshop manual, I knew this is the exact kind of fix I'd been dreaming about. Simple, cheap and often-overlooked. I've had the A/C recharged, it seems to hold the pressure well, no odd noises from the compressor, except that the clutch doesn't engage/doesn't stay engaged for more than 10 seconds after starting the engine, maybe less. It's either this, the pressure sensor, or the thermostatic expansion valve (I have no idea what this is or does), or the compressor clutch, or the compressor itself, easy-peasy. I'm leaning on the evap sensor because it seems the most likely, considering one of the failure modes (open circuit) would present these symptoms.
Symptoms:
-A/C light turns on, so that's a good sign
-No cold air whatsoever
-Compressor momentarily engages and disengages
Questions:
1) I read that the Evap Temp Sensor is an NTC thermistor with 5.3kΩ at 22°C, does anyone know another temperature-resistance value pair so I can match it to an off-the-shelf one? (I don't want to pay ~£130 for this beauty right here) (It looks like a sensor bulb)
I'm not even sure if this is the right part because I found something called the evaporator thermostat (?)
With absolutely no reference to it in the Rave manuals.
2) Do I have to remove the whole fascia to change the sensor/thermostat/mystery temperature thingy?
3) Can I just glue/affix with a thermal pad the 'appropriate' thermistor on the evaporator in its original position and hope that it will work?
4) Any details about the A/C logic, to clarify the hysteresis (?) in the engaging/disengaging of the compressor?
