84' K5 Pwr Door Locks trouble shoot questions

[B.barket]

Wonder if anyone can steer me in the right direction regarding power door locks on an 84' K5. I'm doing a refresh on the interior. My pwr door locks have not worked since owning the truck and its really not a hassle. But I have the door panels off and have put a decent amt of work into painting them and ordered a bunch of new hardware from LMC to make them pretty close to new again. (new trim above the door handle - new padded arm rests - new bottom door carpet and new pwr window & door lock switches. The door lock switches aren't to pricey so I just ordered a couple of new ones so at least they'll look all shiny and new in the door panel even if they don't work. But since I've come this far and have the panels off I thought I may as well take a run at getting them working. So here's where I'm at when I hit the lock switches. On the drivers side with the old switch and with the new switch I get nothing at all. Not a sound from anywhere. On the passenger side with the old switch I also got nothing. But with the new switch I hear a click under the dash. I guess it can be one or a combo of about 5 or 6 things correct?. (Bad switches - bad plugs - blown fuse - bad relay of some sort - broken wire somewhere or failed actuators inside the doors). I have little to no skills at tracing electrical issues. Sooooo what if anything have I missed below?, and what order would you go about this process if it was you?

1) is there anything I haven't thought of?
2) which fuse in the panel is for the locks? (may as well start with the easiest thing to check)
3) I assume one of the holes in the plugs is for constant pwr to the switch - which hole is it so I can check it?
3) what am I looking for under the dash where I heard the click?.
4) what are the odds that its the actuators themselves that are bad?
5) is replacing the plugs for the switches as simple as cutting off the old one and splicing the wires of a new one?

Thanks in advance for any guidance!

 

[6872xtc]

One problem that can occur is the wires can break in the door jambs from the repeated motion from the open and close cycles of the doors. There can be just one, or several with problems. Having the door panels off already is a perfect time to work on them, obviously. I would also check the harness under the dash on both sides just in case a previous owner did something bad. I am fairly sure that the reversing relay for the locks is above the gas pedal, so follow the wiring to it.

I would think that the fuse is good since you hear a click when trying the one switch.

And I think that the center wire at the switch is the power input.

The actuators could be bad, or just bad wiring going to them, combined with very old and dirty grease inside them, hanging them up.
I wouldn't replace the plugs unless you can verify that they are the problem.

 

[B.barket]

^^.. ok so the click I heard in the dash was for sure on the drivers side so that's the "reversing relay".. So that likely means that I'm fine at the fuse panel up to that relay so the issue is somewhere down the like from that point. Thank you for that info xtc.. That at least moves me that far down the trail of wiring toward whatever the problem turns out to be!