Sounds like the pnp switch located on the transmission where the shift cable attaches to the shift linkage. I had to replace mine recently when the weather got cold. I took mine apart and noticed that besides the copper contacts inside the switch, the switch is full of grease. I guess to keep the moisture out. The contacts looked in good shape but the grease was hardened with age. I think this is why this switch fails in cold weather. The hard grease prevents the contacts from working. After your engine warms up the grease everything is ok.

Look at the web sight volvospeed.com they have instructions on how to replace the transmission pnp switch.