Can I put a '94 radio in a '90?

[classicLS]

Fixing up my late-grandmother's old 1990 LS400. The radio is flaky and often does not turn on. I have found on eBay some radios from 93 and 94 that appear the same (both are Pioneer). Are they electrically compatible? Can I buy a 1994 and plug-and-play with my 1990 LS?

I understand I cannot put a Nakamichi radio in it, right?

Thanks in advance

[Exhaustgases]

Okay the parts book shows this for a 90     8612050010    and the 94 only listed the same first 5 digits, 86120. The 90 showed that it was available for a cool $2078. but didn't list it available for the 94 so I don't know what that means.

[CELSI0R]

A 1993-1994 Pioneer stereo can be compatible with the 1990-1992 units, depending on options. Note that 1990-1994 stereos with CD changers have 3 connectors, while those without only have 2 connectors. Also, the 1993-1994 has an extra security light, as well as a different configuration of what each button can do (FF, Rew, Program, etc), but I'm not sure how much this alters the stereo's function.

I created an album on Imgur to help identify all of the differences.

The Nakamichi radio will definitely not work without changing out other audio components first, including connectors.

[Exhaustgases]

Thank you Celsior, it may work, maybe he will try it.

[classicLS]

Thanks for the album.  It helps me compare connectors.  I think they do look like the same 3 connectors, so I may give it a shot.  Thanks!

[Exhaustgases]

Just make sure you come back here and let us know how it all worked.