1994 Mazda b4000 ground issues

[callmedak]

I’ve got a 1994 Mazda b4000 with the 4.0 and I’ve got a issue with the ground running from the battery negative to the rad support getting to hot to the point if it comes into contact with something it’ll start to melt. I’ve got codes related to open or grounded circuit I’ve checked all grounds and they seem to be fine. Any help would be appreciated

 

[RobbieD]

There is a larger ground cable going to the frame then the engine. Sounds like a problem with that larger main grounding cable.

 

[callmedak]

There is a larger ground cable going to the frame then the engine. Sounds like a problem with that larger main grounding cable.

I’m not really familiar with theses trucks do you know where it’s located I’ve looked over the truck and even though the diagrams and haven’t been able to locate the frame to engine ground

 

[RobbieD]

The big negative cable from the battery should go through an eyelet bolted to the frame and then continue on to the engine. One big cable connected to three places.

Cables can rot on the inside beneath the plastic insulation, but still "look" good.

As a test, take one jumper cable from the battery negative to the engine block, away from moving engine parts, and then see if the smaller ground wire to the rad support still gets hot.