A/C Button not working

[OhioTouring]

I have been working to get my 92 525i Wagon back into shape. A couple days ago an overheating issue. Next to make sure that the Aux Fan was working I went to turn on the A/C. Pushed to button and nothing. I ensured that both driver and passenger controls were all the way to cold and fan on. Still nothing. The fresh air recruculating button won't work as well. I checked the fuses and all is ok. The defrost button does work.

It could have been this way for quite some time because I rarely use the A/C.

Does anyone have some suggestions on troubleshooting before I go buying parts. I searched through my Bentley manual and really didn't find anything.

I greatly appreciate any guidance or suggestions.

[Garlic Breath]

If memory serves me correctly, if you have low refrigerant the A/C will not come on.

Another way to test the Aux fan is by disconnecting the connector that goes to the radiator temp sensor and jumper the wires. Brown is the common, so jumper brown to one of the other two. One is low the other is high, memory fails me for the color combination but I'm pretty sure that brown is the common.

[PeterInSTL]

If your refrigerant is low the a/c button and the recirculate button will not light. I had the same problem and once the system was charged they did work. Check the refrigerant level.

[OhioTouring]

Thanks for the quick answers. I have it scheduled next week for a charge.

[Kalevera]

Also -- for what it's worth, the Bentley manual lists the procedure for assuring that the aux fan, ballast resistor, and relays are functional...can't remember the page off the top of my head, though ;)

Welcome to the board, BTW!

Best, whit

[upallnight]

Probably low on refrigerant and the low pressure switch is preventing the compressor from enagaging.

Your is a 92 and unless someone has already converted to 134a, your system came with R12 originally. R12 is only sold to certified tech. If you want to DIY this yourself convert to 134a and try filling the system.