side mirror, cruise control, seat belt warning all don't work

[howardc64]

2000 V70 Cross Country AWD SE 167k miles.

Just bought this car for a friend and going through to fix all the issues. Power side mirrors, cruise control, and seat belt warning all don't work. Previous owner mentioned lift gate's washer also doesn't work. These are all on fuse 29 (10A) and the fuse is good (checked for 12V while fused plugged in). Also checked the power mirror switch connector for power (I believe blue wire but I checked all) and there is no power on any pin with key in position II. Master window control switch works perfectly.

Previous owner did replace the ECM. Not sure if ECM replacement would require any kind of sync with respect to this failing circuit.

Thoughts on where to chase next.

Also great if anyone knows where I can find wiring diagrams for this car. Got Volvo's EWD but its for P2s.

UPDATE:

Looks like the problems are all unrelated.

1. Cruise did work, just needed to get up to speed to turn it on. Call it unfamiliar operator error

2. Power mirror control wasn't getting power due to master window control module's failed circuit to supply power. $0 fix for this below

3. Not sure what seat belt warning is yet, need to chase that next

Found wiring diagram here

http://www.volvowiringdiagrams.com/volvo/V70XC Wiring Diagrams/TP3943202 2000 C70 S70 V70 Early Version Wiring Diagrams.pdf

$0 fix for inoperative power mirrors

My driver window modules works. All the windows go up and down and locks work. Page 26 and 30 of the 320 page wiring diagram provides the key checkpoints. Page 26 shows the driver's side window module (3/97). A:2 is the +12V supply to the module. B:4 supplies +12V to the power mirror controls. If B:4 doesn't show +12V when activating the power mirror position controls, then its likely the varister (the symbol just below B:4 in the diagram) has failed. Verister is basically act as a dampener to flow current gradually to prevent sparks when power mirror controls makes various contacts. But varister seems rather unnecessary given all this stuff is pretty low powered. I just jumped A2 and B4 connection to supply +12V to the power mirror controls. NOTE A2/B4 jumper is for RHD only. Consult the wiring diagram for RHD and Convertible cars.