90 GMC k1500, AAI-GM9

[marc54]

I have a 90 GMC k1500 with stock stereo and slave tape deck and want to add an aux input to the stock stereo.

Will the AAI-GM9 work? Says it works for 95's and up, and I know that is a different radio than mine.
http://pac-audio.com/productDetails....&CategoryID=24

I want to retain the completely stock look and add auxillary jack.

If the above doesn't work, anybody know of one that does? Or if I can tap into the wires going to the slave unit?

Thanks,
Marc