After installing a switch to control the radiator fans on my '79 B, my fuel gauge and coolant temp gauge stopped registering any reading, each of them always pegged to the left. At first I figured that I blew a fuse and ignored the problem. Since I have found all fuses working, I'm wondering how to find the problem. Here are some pics, if they can help.
The sending unit was replaced shortly prior to this event, but was known to be working before this happened.
The green wires are original. I added the red wires to manually operate the fan.
Can anyone give me some ideas?