Fuse what fuse on a 88 monte carlo is the one for my cd player

The 88 Monte came stock with am/fm or am/fm cassette so my guess is your head unit is after market, implying that there may be two in-line fuses on the units power leads

1) 12+ volt Un-switched constant feed (memory)
2) 12+ volt Switched feed (operation)

If you can not locate these fuses from under the dash, then you may need to remove the head unit to inspect the wires that connect to the rear for the in-line fuses.

When you reinstall the unit, be sure to make those in-line fuses accessible from under the dash.

Good luck
Aduz