Grounding frame
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Cross-Country
Joined: Aug 2009
Posts: 60
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Grounding frame
I'm still having some issues with my fuel gauge, I want to make sure my frame is grounded good. My truck is a 79 F150 4x4, From what I've read of other owners they say ground the frame from the motor, I have a 351M engine, just under the alternator is a stud that the negative battery cable from the battery is hooked to. Is it safe to hook a grounding strap from that stud also and fasten it to the frame? Also should I have the ground wire from the tank senders hooked to the frame or is it ok to hook them to the underside of the truck bed?
Lead Driver
Joined: Nov 2006
Posts: 5,217
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From: Pa.
The best money spent for electrical issues on our trucks is the "EVTM" (electrical vacuum troubleshooting manual). Here is a 1979 manual. The EVTM lists the grounding points for all circuits and maps their locations. There's a little bit of a learning curve but it's worth it and besides any questions you have about it can be answered here on this forum.. 
More Turbo
Joined: Mar 2022
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I drilled and tapped a hole in the frame for my grounding points. Negative battery and ground strap from block attach to the bolt. My fuel sender ground is directly to the frame. This also allows you to potentially remove the bed without worrying about an additional wire connected to the bed.
Hotshot
Joined: Oct 2009
Posts: 16,188
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From: Burbank, WA
I'm still having some issues with my fuel gauge, I want to make sure my frame is grounded good. My truck is a 79 F150 4x4, From what I've read of other owners they say ground the frame from the motor, I have a 351M engine, just under the alternator is a stud that the negative battery cable from the battery is hooked to. Is it safe to hook a grounding strap from that stud also and fasten it to the frame? Also should I have the ground wire from the tank senders hooked to the frame or is it ok to hook them to the underside of the truck bed?
FTE Legend
Joined: Nov 2015
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From: Angier, NC
To answer your question, yes, it's safe to run a ground wire from the block stud to the frame. It's good to have redundancy on grounds. I like battery to block, block to frame, frame to body, and body to block, just to make sure all the bases are covered. You can have your tanks grounded to the bed as long as the connections are clean and you have another connection from bed to frame. As mentioned above, grounding to frame eliminates that one extra leg and provides a shorter path back to the battery. Having a good ground strap on the bed to frame will help with the tail lights, so it's a good thing to have anyway. Poor grounding is the number one cause of electrical issues.
Only thing I would not do is the tank sender ground to the bed run it to the frame that is grounded at the motor.
I would run a ground from frame to bed to help the tail lights.
Dave ----
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From: S/W Missouri, Polk county
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Cross-Country
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Thank you for the reply! My sender units are not grounded to the body like I thought, they are grounded to the frame cross members. I am still planning on putting more grounding wires on my truck. So far the only grounds I've found from the battery are the one to the engine block and the one on the back of the block going to the cab. I have cleaned them but haven't found any grounding the frame.
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From: Angier, NC
So you have a nice big ground wire to the radiator support that is sitting on rubber mounts are the head / turn / park lights grounded to the support?
You really need a ground from the motor to the cab so it is grounded.
Also them battery clamps that clamp the cables are not the best to be using long term as the start to turn green under the clamps, you cant see it and stop working.
Either a PO removed it in a motor swap or it never had one but I go with the PO removed.
Just add one from motor to frame.
Dave ----
You really need a ground from the motor to the cab so it is grounded.
Also them battery clamps that clamp the cables are not the best to be using long term as the start to turn green under the clamps, you cant see it and stop working.
Thank you for the reply! My sender units are not grounded to the body like I thought, they are grounded to the frame cross members. I am still planning on putting more grounding wires on my truck. So far the only grounds I've found from the battery are the one to the engine block and the one on the back of the block going to the cab. I have cleaned them but haven't found any grounding the frame.
Just add one from motor to frame.
Dave ----
Cargo Master
Joined: Nov 2007
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Large cable from battery to body, battery to frame and battery to engine. Then some heavy wire from frame to engine, frame to cab, frame to bed, frame to both inner fenders, frame to radiator support and one from the engine to the cab. Solder all the ends on and use star washers under them to make sure you're getting a metal to metal connection. I'm sure someone's going to think it's overkill, but even with the cost of the large ground cables, it's a pretty cheap, easy and relatively quick upgrade that will ensure you will never have ground related issues again.
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