Superbacon

I'm a driver of a 2008 Civic Hybrid. Purchased June '17 with no problems.

Back in May this year I went on a trip to EDC Vegas where I was out of town for close to a week. I left my car parked at my friend's place in northern Illinois. After getting home I found the alarm on my car no longer set from my key.
It still locks (no flashing lights), unlocks (with lights flashing), opens the trunk, and the panic button works. True for both keys. But I got it to set once from the spare key, but only once.
I suspect a fuse might have blown in a heat wave while I was out of town. I just don't know where that fuse could be. There aren't any fuses for the anti-theft or alarm under the hood or by the left knee. Unless it isn't a fuse. I figure this has to be isolated to the alarm system since everything else works. All doors and windows are definitely closed.
The only thing I've tried so far is replacing the horn fuse which did nothing.
I'm thinking I'll go to my dealership to try and diagnose the problem but I want to try and fix it myself. Haha I just need to know what causing it. Anyone experience this before or know what's the cause?

CraigW

iTrader: (1)

Do you have the red/orange indicator in dash (flashes when alarm is set)

No lights when locking may be a sign of issue.

On my 2010 LX just closing all doors will set the alarm.

ezone

If the hood latch has a microswitch on it, it may be bad.

Superbacon

I checked for the red flashing light on the dash this morning and it wasn't there. Which indicates the alarm isn't set.

Superbacon

How can I check for that?

GolNat

iTrader: (7)

Look for a small switch around the hood latch area. If its an aftermarket alarm it usually looks like this:

ezone

The hood latch will have a connector with 2 wires in it. Ohm check, switch should be open circuit when the hood is closed. Unplug it and see if the alarm will then set.

OP: Factory alarm does not use any of those.

Superbacon

I found the connector to the hood latch and disconnected it. The alarm sets now just like it should. Thank you.

What now though? Should I have the connector replaced or should I just leave it be?

ezone

The switch in the latch isn't working.
Honda sells the hood latch complete with switch.

Of you could take it all apart and try to discover if you can do anything with it yourself to make it work again.