Code Alarm Doors Wont Unlock

This is for a 96 Toyota T100 truck. It doesn't have electric door locks from the factory, aftermarket actuators must've been installed.

My Code Alarm car security system just died. I can still lock all doors
with the keyless remote but, the remote can't be used to unlock the
doors. I can hear a click noise from under the dash (drivers side) but,
it won't unlock the doors. I tried using a spare set of keyless remotes
but still same result. At this time entry is only gained by using the
key in the door. When parking the truck, usually the doors
automatically unlock when turning the ignition off, now the doors
remain locked. You can still hear the weak click noise under the dash
when you turn off the ignition. To exit, you must manually unlock the door to get out.

I bought the car used and it had an aftermarket security system install

in it already. No alarm, just a keyless entry system and an ignition
switch cut out and a red led flashing light on the dash.

Can anyone offer me any tips/suggestions on how to fix this?

if you are hearing a clicking noise, then the keyless is doing its job. check the relays that control the actuators. the unlock is probably not getting constant or ground.

is the click that you hear the same click as when you use the door lock swicth manually? if its not there is something wrong with the alarm outputing the lock/unlock trigger. might check to make sure a plug didnt come out of the alarm brain.

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There are 10 types of people in the world, ones that understand binary and ones that dont.

Thanks everyone for the suggestions. I tore into the unlock relay housing and found that the relay contact was eroded away. The keyless remote signal was doing its job but, the amount of contact in the relay was too minimal for the actuators to get the message. If I forced the relay closed with my fingers the actuators got the signal and unlocked the doors. So, a local car stereo/alarm shop provided a new relay for $3.00 and all is working well again.