2004 Civic Value Package sedan. A/T. 65K miles. Purchased 3 years ago

Mom's car... she said horn went off intermittently a couple times in the past week while she was parked and yesterday when she opened the trunk. Horn goes off when opening trunk or passenger door and driver's door with key. Value Package does have door actuators or key-less remote. Has the stock anti-theft device only and no issues previously.

1) I removed negative terminal. drained residual charge, replaced to reset ECU .. didn't fix.
2) Checked for hood latch sensor and it doesn't have one

Recent Repairs (I did)
1) Valve lash adjustment
2) Valve cover gasket
3) Cam end seal/plug
4) Cleaned engine and transmission with de-greaser

Recent Dealer Repair:
1) Air-bag recall fix (3 months ago)
2) Door Switch part# 35400-S5A-013 last week that seem to work for a day or two but, failed to fix alarm/horn issue as, it going off again.

All suggestions, comments appreciated

 

Turns out car must have reverted back to Valet Mode when I disconnected the negative terminal (24 hours) for a recent valve cover and cam plug repair. The key-fob can be activated to alarm/dis-alarm factory anti-theft device to use in Valet Mode. Valet Mode can be bypassed by inserting key into ignition three time in three seconds. My mom opted to have it bypassed.The dealer installed a new battery and back on key-fob in the event she ever wants to set it back into Valet Mode..
No reference in owner's manual concerning valet mode..which sucks.