Dual tank switch blowing fuse

[Tanaga]

I have a 1990 V3500 crew cab with dual tanks. Every time I switch tanks the fuel blows. Once the fuse blows I have no fuel gauge. Any one else have this problem? Any tips of how to fix this?

Thanks

 

[bucket]

Unplug the connector from the switching valve and then operate the switch, with the ignition on of course. If the fuse still blows, it's a wiring issue. If the fuse does not blow, it's likely a shorted switching valve.

 

[Tanaga]

Unplug the connector from the switching valve and then operate the switch, with the ignition on of course. If the fuse still blows, it's a wiring issue. If the fuse does not blow, it's likely a shorted switching valve.

Thanks I’ll try that and report back.