Recently had to replace the air con clutch coil. They also replaced the air con fan sensor. See photos. When it came back from the shop, the engine check light was on, but I don't see anything obvious? Guess they must have disturbed something? But what???
Also, what is the small beige box attached to a wire going to the coil? The new coil lacks this part.

 

There is a 2 wire engine coolant sensor atop the thermostat housing , this regulates engine closed loop and a engine CEL code and nothing to do with A / C

There are 2 A / C freon pressure sensors that will turn on the radiator fans with A / C

The lesser number of wires freon pressure switch was removed by a TSB and the connector jumpered



You may see a jumper plug on the 2 wire connector or the wires spliced

This will turn on radiator fans to low mode on ignition key rotation ( saves the radiator fans fuses from blowing )

There is a climate control self test here on Youtube , but the test does not " see " everything like lent on the cabin temp sensor degrading system performance

 

Please see attached photo of Air Con Pressure Sensor. Before fitting the new sensor, the fans ran slow all the time.

After fitting we charged with gas at 40 psi. But it was not cold enough. So upped the gas to 50 psi (normal for 90 degree heat here in Thailand).
After charging to 50 psi the air is cold ok but the fans run fast all the time and refuse to switch off.

Is the sensor so hypersensitive? What psi should we have?

 

With lent on the cabin temp sensor it will bias the climate control , might clean it without using solvent ( there is a mini fan that draws air into sensor , bearings that can dry out )

This may " balance " your system and get your pressures in range to operate the fans in what you would expect

In general terms if the radiator fans do not dissipate the wanted to expel heat energy ( Q ) the freon pressure will build until the over pressure switch as the 4 wire switch will drop out your compressor clutch , this 4 wire switch does remain after TSB jumpering the 2 wire switch )

There is also the outside air temp sensor with the connector exposed to the elements in the front left wheel brake cooling duct from your front bumper

The cabin temp sensor is the small square louvered opening below the steering column that I'm afraid the whole lower kick panel has to be removed to get to car's front side of the panel

There is a control panel self test on the climate control that you can do seeing other things but does not " see " lent or marginal connectors , this will give you codes against a list

A common thing from reading causing performance issues is the thumbwheel on the center vent , this item was negated on the same Denso climate control system on the later X308

I try to find the codes list as the same as the X308

 

Speaking on balanced there is the thing of the thermo expansion valve getting clogged by the beads coming loose from the freon dryer so not to flow " correctly "

Dryers don't last forever and they let the beads loose clogging the TXV

Motorcarman has a way of clearing the TXV without removing it as buried in the dash just on the car side , but it does involve removing the freon but will get you to optimum this system designed performance