The panel on the door may have failed. On 4 door P80 chassis Volvos it is common at this age. The contacts burn out. Sometimes if you like a challenge, you can disassemble and try cleaning the contacts. I have had some success but it is not a 100%. I have not worked on a 2 door assembly but believe ...

Go to the RH door and push and release the lock button on that side. It seems that a stuck button anywhere results in the VGLA module for locks and such on the 98-04 shuts down.