As Todd mentioned the S 60 harness was designed for 1985-1987 L-body's
These cars had a 40 pin bulkhead connector so the S60 harness plugged in.
All 1988 SMEC and newer cars went to a 50 pin bulkhead connector.
As Todd was using the S60 harness he needed a 40 pin bulkhead.
His 1988 had a 50 so he swapped it out for a 40 pin bulkhead.
With L body's the bulkhead is part of the dash harness.
I think you mentioned you have a GLH or GLH-T
Either one should be a 40 pin bulkhead.
GLH will need a fuel pump wire.
Thanks
Randy