Bingo!
Also check or just get a new Lug to Lug to Lug Battery Cable an go from Bat - to Engine Block and Fender (Chassis)
There is probably a Ground under the floor mat/carpet on the Drivers side to check also.
I agree. This is a good idea for any vehicle on which you are replacing cables, regardless of how it was configured from the factory. Many older vehicles have either "BAT to Engine Block" or "BAT to Chassis". "BAT to Block and to Chassis" is best.
Cowman, the cable will have a battery connection at one end, and also TWO mounting lugs. one will be partway along the cable and one will be at the other end from the battery connection.
If your truck is not already configured for such a cable you'll need to do some measurements so you can buy a "generic" cable with sufficient length(s) to be able to run it from the Battery to the engine block (intermediate lug) and then from the block over to the chassis (the end lug).