I have an install issue with a new JVC deck. Here is the issue... I have two 1995 integras.

1995 GSR
Alpine head unit

1995 LS
JVC head unit

Plug both head units into GSR and everything works fine. Plug either into LS and nothing works. Plug factory deck into LS and everything works fine. Could it possibly be that the factory harness terminals are shorter on the LS? Because the 15 amp fuse for the radio/cigarette lighter is fine (has also been changed).

I would appreciate any help with this, thanks in advance.