I got the new pickups and installed them - GFS neovin pickups. They have a black ground, a silver ground, a red and white for coil tap but the are twisted together on all pickups, green wire for each pickup to the 5-way. What's happening is this:

When 5-way switch is in the neck position, it sounds great. Full volume and tone is there.

When 5-way switch is in the position between the neck and middle pickups, the volume drops significantly but is there.

When 5-way switch is in the middle pickup position it sounds great again - full volume and tone.

When 5-way switch is in the position between the middle and bridge pickups the volume is very faint.

When 5-way switch is in the bridge position, I get no volume at all.

I've measure for resistance between the pickups and their solder points on the 5 way switch - everything appears to be good. Also measured each switch position to the volume pot - each connection on the 5-way switch shows continuity between the correct pickups and the volume pot.

How else can I measure to find out where the issue is? I have not plugged it in and measure yet as I'm not an electricity expert - but I can be careful and my multimeter will read AC voltage.

Any recommendations?

pic of the switch and the volume pot: