Rear door latch

Is there a micro-switch in it to indicate the the door is open ?

There is no rear courtesy light and no indication on the dash when the door is open.

I need this to connect to a newly fitted alarm.

I've never found it but there must be one in there because I don't see any other switch anywhere. Maybe it got salty?
(BTW make sure your spare wheel thread is not too salty).

Also bear in mind the rear+middle courtesy lights are on a different circuit to the front ones so you'll need diodes to feed both signals to the alarm (else it will just join them together as one).

Had the alarm professionally fitted and it is activated by either cabin door and also the side door (along with intrusion detectors within the front cabin).

However it is not activated by opening the rear door and there is no visible switch on the rear door, so it is not currently an official Cat 1 install.

Installer says he "thinks" there is a micro-switch in the rear latch which must have failed. However there is no rear roof mounted courtesy light, just a blanking cover in the same trim as the rear roof mounted moon roof switch. So the only reason for a microswitch in the rear latch would be to illuminate the "doors open" indicator on the dash.

Mine operates the middle lamp too I think + the dashboard lamp.

Have a look at this:
https://www.ebay.com/itm/Replacement-Tailgate-Rear-Back-Door-Lock-Latch-Fit-Toyota-Hiace-Dyna-69350-95J01/182497553077

Looks like a switch in there to me - maybe it's easy to change?

Seen a few of them knocking around on eBay.

Took the trouble to remove the 3 securing bolts earlier this week and it was simple enough, but the mechanical connection to the remote locking looks more than a little awkward.

..... Stuff it..... fer £10 ? ...... ordered.

UPDATE~

Fiddly replacement...... not difficult.

Dash warning light now indicates the rear door is open, so the alarm is activated.

Problem solved.

Interesting point.... there is an additional, unconnected white wire along with the 2 that connect to the latch. Any idea what this might be ?

Unused supply for a rear cabin courtesy light perhaps ?

Great news!
No idea what the white wire is though