91 Cadilac Seville bypass of bose

Wondering if anyone knows or if its possible to bypass the bose gold series premium sound. The cars a 91 Seville. We replaced the headunit and the rear speakers which we ran new wire straight out too. The front speakers are still running off the factory amps. I used a signal atenuator to decrease the signal to the amps. Now it all works except I'm getting a nasty altanator whine and noise in my front speakers. If I could completly bypass the amp it would be cool. Its got a four wire plug on it. Orange, black, yellow, and I think blue not sure on the last color. Orange is 12volt. None of them read ground and when you check impedence their all over 10000 ohms. Doing this without replacing the stock speaker would be a plus. Any help would be greatly appreciated. Thanks

You need Metra wiring kit number 70-1857 for GM Bose.  With this you can bypass the factory amps.