92 Peterbilt 377 Gauge Problems

Well I tried the head gun today. I actually already ordered a new sensor for the coolant gauge and used that instead of pulling the old one.

Hooked up the sending wire to the new sensor and ground it to the frame. Nothing happened. So I rigged up some jumpers and went from sending unit straight to gauge and grounded it again. Gauge worked fined when I applied heat.

I’m thinking I’ve got a broke wire somewhere. Any idea on a schematic to trace wire out? Thinking maybe if I could find where it’s broke I can fix oil temp too.

 

Alright I’ll post and let you know how that goes