LF: Zexel thermosensor

**oj88** · May 19th, 2019 09:07 AM

Originally Posted by jakewise

Thanks for your input and I am fully aware of the other variables. It is just that the car is showing the same symptoms I had years back when I was forced to replace the thermosensor.
Earlier, I was at the local aircon parts supply here in the province and they confirmed that the mechanical thermostat has a different calibration from the electronics thermostat which confirmed my theory earlier. In this regard, I have no choice but to look for a supplier for the thermosensor.

So let me get this straight... The OEM sensor is the Zexel part no. you mentioned in the beginning of the thread. Then it became defective, so a mechanical thermostat was used in its place. That’s when your issue started happening (compressor turns off prematurely). Did I get the sequence right so far?

If yes, here are my questions:

1. What were the problems or symptoms you encountered that prompted you to determine that the OEM sensor (Zexel) was the culprit?
2. Did the issue with the compressor prematurely shutting down happened immediately after installing the replacement mechanical thermostat, or did it only started happening after a while (days, weeks, months, etc.)?

**jakewise** · May 19th, 2019 09:42 AM

Originally Posted by oj88

So let me get this straight... The OEM sensor is the Zexel part no. you mentioned in the beginning of the thread. Then it became defective, so a mechanical thermostat was used in its place. That’s when your issue started happening (compressor turns off prematurely). Did I get the sequence right so far?

If yes, here are my questions:

1. What were the problems or symptoms you encountered that prompted you to determine that the OEM sensor (Zexel) was the culprit?
2. Did the issue with the compressor prematurely shutting down happened immediately after installing the replacement mechanical thermostat, or did it only started happening after a while (days, weeks, months, etc.)?

Yes, the part number I mentioned is the part number of the OEM sensor.

1. The airflow would become minimal unless you turn off the compressor by its push button switch that would say that the evaporator is icing. After a while, when I turn on the compressor again, air flow will be back to normal and cold air again will come out.

2. Yes, the issue would prematurely shut down when we replaced it with a mechanical thermostat.

**ParticleX** · May 19th, 2019 09:49 AM

dunno if this is similar to your part

Zexel thermosensor 582550-9900 12VOLTS 24Z8D3 2.5 ºC

**jakewise** · May 19th, 2019 10:10 AM

Originally Posted by ParticleX

dunno if this is similar to your part

Zexel thermosensor 582550-9900 12VOLTS 24Z8D3 2.5 ºC

Thank you, I saw this also. It has a different part number and the calibration is 2.5 degrees Centigrade, but if I cannot find exactly like mine (calibration is 3.5 degrees Centigrade), I might have to jump and try my luck with it.

**oj88** · May 19th, 2019 11:21 AM

This part (582550-5901) seems quite rare. Isuzu isn't as common worldwide as the other brands like Toyota or Honda. But worst case, you could try tweaking the current mechanical thermostat to make the sensing tip less sensitive to the cold or move it further from the evaporator coil.

By the way, is the sensor installed upwind or downwind of the evaporator? Can you post a picture of the mechanical thermostat?

**jakewise** · May 19th, 2019 02:26 PM

Originally Posted by oj88

This part (582550-5901) seems quite rare. Isuzu isn't as common worldwide as the other brands like Toyota or Honda. But worst case, you could try tweaking the current mechanical thermostat to make the sensing tip less sensitive to the cold or move it further from the evaporator coil.

By the way, is the sensor installed upwind or downwind of the evaporator? Can you post a picture of the mechanical thermostat?

Although it may true that the part number may not be as common as the others, I might just try my luck with other part numbers as long as it is also a zexel thermosensor (with different calibration). I found two in ebay but it has a 2.5 and 1.0 degrees centigrade calibration.

I disposed of the mechanical thermostat already although it is a typical thermostat that all aircon shops seem to sell, it is "Made in Mexico". I planned to tweak the mechanical thermostat and asked the aircon technician if he can do it, but he replied to the negative.

I posted earlier on the this thread the picture of the thermosensor but I am not sure if it is upwind or downwind of the evaporator.