I have a 2005 Lotus Elise and I have been troubleshooting the AC for over a month now. Listed below are the things I have tried.
1. Checked all fuses...both under dash and under access panel.
2. Replaced thermostat with upgrade kit
3. Replaced resistor pack with relocation upgrade kit.
4. Switched out relay pack over passenger wheel well.
5. Checked coolant level and pressure.
The blue light on the ac control turns on and the fan runs.
If I apply power directly to the compressor it turns on and blows cold.
If I power the compressor fuse under the dash the AC turns on and blows cold.
Things to note. I bought the car last winter in Wisconsin so I thought the ac was blowing cold but it was also 15 degrees outside so I later found out I was mistaken.
Before I owned it, (in 2012) the car had a BOE REV400 with a DRS x-2 EFI and mil spec harness installed by BOE. The car only has about 1000 miles since the install. The reason I mention the x-2 EFI is it is the only thing left I can think of that would cause the AC compressor not to turn on.
If anybody had any ideas or can help I am literally pulling my hair out.