Air suspension microprocessor

I took my 03 navigator to the dealership because the air compressor was not kicking on and the check suspension warning keeps coming on. The dealer told me that no power was getting to the compressor and I needed to replace the microprocessor ($1150). Then he proceeds to tell me that the compressor might be bad but he couldn't check it until the microprocessor is replaced. Has anyone ran into this issue? I feel like I'm getting screwed royally. Of course this happens at 50,700miles (no more mfr. warranty).

I am not sure if the 98 has the same system or not, I ahd problems with my pump not kicking in, There is a small type computer thing underneath the right headlight area mounted to the frame. It is a type of relay but not a relay like normal cars, It might be called a microprocessor not sure.

More than likely it is the pump, like $200 or so, I would replace it and see if that worked before I replaced the $1150 thing, also what is the part cost, maybe it is labor that makes this so high, I changed my pump myself it was easy. I also swapped the relay thing to check if it was bad myself it was very easy.

TIM