how can I get my JVC KD-S30 to work in my "94"saturn SL1?

How can I get my JVC KD-S30 to work? I have made all connections. Power works. Power output is 14volts. I have reset the unit. The entire unit does nothing. No response. What is Worng? Are some units not compatible with some cars?

I have a 5sdp "94" Saturn SL1. There was a small amount of oil on the unit the second time I attempted to install it. Temperature of the car was 40 degrees - 50 degrees max. Original sterio unit work on existing wireing.