Just got a DOA 1988 F150 and thought I'd start by replacing frayed and corroded battery cables. Got them directly from Ford.

Wiring diagram and conventional wisdom tells me that the POS cable goes to the starter, but the wires I got are BLACK to the starter and RED to the terminals on the fender.

Before I drop in this new battery and fry the electronics, is the NEG terminal supposed to connect to the starter? Or am I just getting this all wrong?

Thanks!

 

Are you sure the negative cable goes to the starter? In many cases, the negative cable bolts to the engine block, right next to the starter. The ground bolt and starter are so close, in fact, that in many engines, the negative cable looks like it goes right to the starter at first glance. If you get closer, you may find that your original observation is an illusion.

Traditionally, the negative cable goes directly from the negative battery terminal to the engine block for ground. The positive battery cable goes to one heavy stud on the starter solenoid, on the fender. This "side" of the solenoid feeds all +12V of the vehicle's electrical system, so at this spot you will see a few other wires branching off.

The other heavy stud on the solenoid goes directly to the starter. You will see one or two smaller studs in the middle of the solenoid. One receives +12V when the ignition switch is turned to "start," and grounds on the fenderwell. If you see a second post in the middle of the solenoid, I believe this is for a spark retardation for a Duraspark system.

 

Thanks - I'm strictly amateur, so bear with me. Based on your response, I'm guessing that yes, the negative cable is the black one and the positive cable is the red one (as it should be). I'll have to take another look, but the negative cable goes from the battery down into the engine compartment (it is about six feet long). right in the middle, it is grounded to the frame. At the end, it connects to what I thought was the starter, way under the truck, but this is where I probably have it wrong.

The positive cable is much shorter, maybe 12 inches, and connects to the solenoid on the fender. As you describe, there are a number of other wires branching off here.

So I guess the conventional red to POS, black to NEG is correct here. Still not sure where that neg lead is connected though...

 

You're correct about the convention; red is usually positive and black is usually negative (ground in this case). On these electrical systems, an all-black wire is almost always ground.

I'm a bit confused about how you described your negative cable, though. On one end you should have the battery terminal connector, and on the other end you should have a heavy-duty ring terminal that is bolted to the block. What does this middle connection you're speaking of look like? Are you sure it makes an electrical connection to the frame, and it's not just a support strap to keep the cable in place?

The only lead to the starter is the heavy-duty lead coming from the solenoid. I beleive the starter grounds through the bellhousing. If you trace your negative battery cable carefully, you will find that it terminates on the engine block.

 

This negative cable is essentially grounded in two places; the connector in the middle is bolted to the frame, and the very end is bolted to the starter case. The connector in the middle is definately a ground connection; the cable is not insulated at that point, and there is definately metal-to-metal contact. Not like anything I've seen before.

 

Someone has changed this around. The negative should go to the block first. Then small ground straps go from the block to the sheetmetal on the firewall and various other places.

Somewhere along the way, an engine change has been done, or the negative cable went bad, and someone was having grounding problems. Sometimes when the negative cable goes bad, the starter tries to use the small grounding straps for a ground, and they get burnt up. Other times, the engine is changed and someone forgets to hook up the small straps to the new block.

For whatever reason, they have run a ground to the frame. And then it probably runs over and bolts to the starter housing for a ground. It should work ok this way, so long as the new connection on the frame does not get water splash on it all the time and starts corroding.

 

Thanks for the input, but the wiring as I have described is the original design. Both the original cable and the OEM replacement from Ford are fashioned with this ground screw/clip halfway down the cable bolted to the frame, and the end of the cable is bolted to the starter housing.

 

I am doing this same procedure today and actually had this exact same question. Total amateur here. Did this get resolved?

I have a 1986 F150 4.9L 300. Trying to change my NEG cable and noticed the same "double ground" PotomacEd mentioned.

Battery terminal connetor > "middle" ground connector > ring terminal connector. There's also a small wire coming off of the terminal connector (looks to be low-voltage). Is this for the computer?

I thought the "middle" connector was simply a support strap to hold the cable in place. It's connected to the frame system, next to the engine block. When I took it off I realized that the connector was actually heavy guage metal and bare wire is underneath. The connector also can't be removed. The ring terminal end of the cable connects under the chassis to the back of the starter.

I've attached a couple of pictures showing the middle connector & where it was connected on it's was down to the starter.

I just bought a replacement cable from an auto parts store and now that I see this, I'm not sure it's ok to use it. This new cable doesn't have the middle ground connection.

Thanks!

 

This thread is over 10 years old and I have learned some things along the way. I am not sure about other years, but in the 80's the six cylinder truck's usually had their ground hooked directly to the starter housing. The v8's ground was attached to a bolt/stud on the front pass side corner of the block.

And yes, most of them did have a bare spot in the cable and this was bolted to the frame. This grounded the frame. This is necessary, since the cable end is bolted to the starter housing or the engine block, but the engine, transmission and rearend are all mounted in rubber mounts. Even the rear springs are mounted in rubber. So there is no reliable ground to the frame. This is also true of the body, the body is mounted to rubber body mounts which isolate it from the frame and the engine block. So that is why the strap at the back of the engine to the firewall is so important. My 89 f250 also has a strap under the pass side door area that goes from the frame to the body.

You can peel back the insulation on your new cable and try to use the old clamp around it, or you can get another short fat cable and run it from the frame to the block/starter.

 

Thanks so much for the quick reply and great information! Makes a lot of sense.

Unfortunately I can't find an OEM replacement like PotomocEd was able to do, so I'm going to try the second option you mentioned. Just bought a shorter "jumper" cable to run from the starter to the block, then "stack" each cable's ring connectors at the block connection point to run to the battery terminal.

Thanks again!

 

No need to run from the starter to the block. The starter is bolted to the block, so that is a very good grounding connection already. You need to run from the block or the starter to the frame with a short cable.

 

Thank you so much! Struggling with just this, helping a friend... Will have it done tomorrow now!