It could be low on coolant. If your vehicle is a 2002-2004 it is probably the magnetic clutch relay as it is a common problem with those years. It is located in the fuse box and a new one runs around $60.
You need to have a mechanic service your car. The flashing light means the compressor is not engaging.
It's either low on charge, has bad wiring, needs a new pressure switch or needs a new clutch.
You will have to figure out why: This the 90% of the time failur: Is there Freon in the system, if there is not a minimum pressure, usually 17 PSI, the compressor will not run. Is the compressor and clutch capable of working? Is the fuse in good shape.
Lexus Ls 400
check the a/c clutch when those go out the whole system shorts out
To let you know the system is armed.
it would be a 5 by 6 belt for a magnum for a Lexus you would need a 3 by 7
I would look at the REAR signal light on the same side of the car. It is probably not blinking at all and the bulb needs to be replaced.
You add freon to the low side fitting,top front,on the ac compressor
Are you sure it is the A/C Compressor and not the power steering pump? LS400, SC 300 and SC 400 are known to have power steering pump issues that leak onto the compressor causing ac compressor failure. Replace the pump as soon as you see a leak.
Bring to a shop that has an ABS scanner
No, it is not needed because the intake charge is at ambient temperature already( hasn't been compressed by a compressor).