Negative Battery Cable Question

[BlakeusMaximus]

My old negative battery cable that was in the car before I bought it doesn't have the ground that goes to the apron. I looked at a replacement and all of the aftermarket ones from "parts are us" don't have it either. They just ground the the engine on top of the A/C bracket. How big of a deal is it to run one of those aftermarket cables? Seems to run and function ok.

 

[BlakeusMaximus]

Dont everyone speak up all at once!! Just wondering what the differences are, if any.

 

[Dan02gt]

You'll be fine without it. The main ground should connect to a stud on the side of the motor underneath the AC compressor.

 

[BlakeusMaximus]

I thought so, I was just looking at my buddys 93 and he has a ground on the lt apron and not on under the ac compressor. Ive also had some troubles with it starting and wondering if that could be part of the problem.

 

[Nutty 5.o]

If it drives you nuts, you can get the Ford negative ground cable from RA for $24.79 assuming you have that mating connection.

https://www.rockauto.com/en/moreinfo.php?pk=381681&cc=1133985

 

[Dan02gt]

Now that I see the factory connector that Nutty posted, the small fender ground you are talking about is for the computer. It comes from the computer, attaches to the fender, then jumps to the negative side of the battery. You should connect it. Most people cut it off of the negative battery post clamp of the factory cable and connect it to the new setup via ring terminal.

 

[BlakeusMaximus]

Why would someone cut that off??

 

[Dan02gt]

You have to cut it off if you replace the negative battery terminal. Here's mine.

 

[jrichker]

The picture shows the common ground point for the battery , computer, & extra 3G alternator ground wire as described above in paragraph 2. A screwdriver points to the bolt that is the common ground point.

The battery common ground is a 10 gauge pigtail with the computer ground attached to it.
Picture courtesy timewarped1972

Correct negative battery ground cable.

3.) The computer's main power ground (the one that comes from the battery ground wire) uses pins 40 & 60 for all the things it controls internally: it comes off the ground pigtail on the battery ground wire. Due to its proximity to the battery, it may become corroded by acid fumes from the battery.
In 86-90 model cars, it is a black cylinder about 2 1/2" long by 1" diameter with a black/lt green wire.
In 91-95 model cars it is a black cylinder about 2 1/2" long by 1" diameter with a black/white wire.
You'll find it up next to the starter solenoid where the wire goes into the wiring harness.

 

[General karthief]

The grounds are very inportant for efi cars, your negative cable from the battery MUST connect to the engine block, there are two grounds that depend on it. Also two grounds that connect to the body, the one jrichker shows on the fender apron and the one at the back of the head to firewall on the drivers side.
Connecting the battery ground to the ac bracket is like butt connectors, each connection can/will have some resistance, oil, dirt and corrosion over time degrades the connection and will cause more resistance,

 

[BlakeusMaximus]

So it's ok for the negative cable to be grounded down there by the ac compressor bracket??

 

[General karthief]

If it's bolted to the block, yes.

 

[bruno]

You have to cut it off if you replace the negative battery terminal. Here's mine.

Dan,
That's a clean looking setup. Where'd you get the terminals? Is that heat shield fabric around your wiring?

 

[Dan02gt]

Bruno,

Thanks. The terminals are JL Audio XD-BTS ultra compact terminals. The wire is 4 ga NVX OFC (stuff used in high power auto installs) it's high strand count and really flexible. The stuff wrapping/protecting is called Techflex. It's kinda like a Chinese finger trap lol. You can get everything from Amazon or somewhere like Sonic Electronics.