Technical Ron Francis AP-97 Wiring Harness Help

Hi everyone I 2nd hand bought a ronfrancis wiring harness. I didn’t have the wiring diagram so I called ronfrancis and they sent one over. The diagram didn’t have where the two panel wires go (panel ground an panel positive). I called them again and I got blown off, any help would be much appreciated!


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One terminal is unswitched power, the other is switched. To identify, check for continuity between the headlight fuse and the terminals, the one the fuse reads to will be unswitched. The other terminal will read to any accessories, like the radio, heater, turn signals, etc.

Fuse panels don't have grounds...

 

This one does, I’m the one who took the wires off just don’t remember


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OEM's have a ground from ignition switch.

It's possibly the ground signal that later ignition switch's have for idiot light check while in crank position.

 

Also in photo I see Horn Button & Horn (S). Is that relay for the horn? If yes it needs a ground. Time to power up and test.

 

On a horn relay, the input from the horn button is the ground, so that panel still won't have a separate ground. I don't see anything on that panel that would require a separate ground.

Those two connections are both input power; one is unswitched power for loads that should have power even when the key is 'off' like headlights, taillights, brake lights, the other will be all the key switched loads like the radio, heater/AC, wipers, etc...

Easy enough to check with a meter....

 

I agree about horn button being ground. But with out it being in my hands and no back round with this product I'm just speaking as if I were going to test. Pull relay out and do a continuity test from ground terminal (second up from bottom right) to relay socket at 86.

 

Ok, The Panel I bought is a Ron Francis Ap-97 Unit. The wiring diagram shows where to put the two wires... One is black and labeled panel ground and one is panel power. The Red one goes to the starter and the black one goes to the frame as a ground. I know this for a fact. Unfortunately the diagram doesn’t show on which prong the wires go.


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OK, last try….

THERE IS NO GROUND CONNECTION!!! You either have the wrong diagram, or are reading it wrong. This panel was last produced in 2003, so you may have talked to somebody at Francis that doesn't know what they're talking about...

Those two terminals are both power inputs, end of story. TO VERIFY, USE A CONTINUITY METER BETWEEN THOSE TERMINALS AND THE CIRCUIT CONNECTIONS! Make sure good fuses are in place for each circuit, and both of those 60A fuses are good.

What you'll find is one is connected to headlights, taillights, brake lights, alarm/door locks if listed, emergency flasher, lighter. Also the horn, but you won't get a reading because of the relay. These are all items that should work with the key 'off'.
The other terminal will be connected to items that should only work when the key is 'on'; radio, heater/ac, wipers, turn signals, power windows/seats.
I don't know how the individual circuit terminals are labeled, so you may find variations, and I'm sure this isn't all the available circuits.

15 minutes with a meter will confirm this. If it doesn't, the panel has a problem. Virtually every 'unified' fuse panel used in vehicles since Detroit started installing them is configured this way, yours included.

You're not getting the answer you want because it's the wrong one....

Maybe if you post the diagram Francis sent you along with a better pic of the panel that would clarify things.

 

The first pic shows a terminal labeled "ground" a couple of spaces below the purple wire. Don't know why it's there, but if it's a ground going from the panel, then there has to be a ground going to the panel - don't ya think?

 

Meter between the terminal labeled ground and to each of the terminals on the back of the panel. If you get continuity from one to the other, I'll bet you've found your ground.

 

Just cause someone put a wire on the bottom lug that is black and is marked ground doesn't make it right, I have seen cars wired in all black wire. Honestly the side terminal near the neutral safety is the ground for the unit man. The bottom two are power supply to panel, and other is key on as stated before. I will say that there is no reason for a huge ground wire for this fuse box, reason being you are only tripping a few relays off supplied ground at best, so that's a few milliamps of current, 18 gauge will do you fine there. Main terminals to bottom need to be minimum of 8 gauge for main panel supply if under 10 ft from batt, if longer then you may bump up to 4, and probably 10 for ignition on acc....

 

Hi everyone the problem is finally solved via official reply from Ron Francis. As I thought the black wire goes to a frame ground and the positive to the starter. They attached this picture to the email which solved my problem. Thank you everyone!





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Mystery solved! Thanks for the follow up. Things are not always as obvious as they seem...

 

When you're done and half the panel has no power, this will be why.... I tried....

 

Could it be that there is another +12v switched (key on) feed coming to the panel? If you look carefully at the first pic Ceegan posted, it looks like there's a screw terminal with red dividers on each side just above(below) the 60A fuses. Without having the panel in front of me and having the ability to meter a couple of things, it's difficult to rule out what Ron Francis did, or why they did it. Stranger things have been done.
I'd like to see more pics of the panel and an update on what works and doesn't when installed - I like surprises!

 

I thought that you would hear from the bunch at Ron Francis. That is a class company to work with

 

Ok I will update when it’s all said and done... if I remember.


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I’ve called them numerous times with different question they do have incredible service!


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Best to perform a continuity test for each terminal to each 60amp fuse up front before any power is applied.

 

If you are convinced there is only one power feed then why two 60 amp fuses? I don’t know why you would need a ground to the fuse box, it is for power distribution, I would be curious to see how it tests with a meter.


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Could they have done it for fiberglass cars?

 

Even then it doesn’t make sense to ground everything to the fuse panel, run a common ground off the battery to somewhere.


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I think the question comes about because this fuse panel is asking for a ground wire. But only on the face side. The red cap and black cap on the back side may have an entirely different meaning than + and -.

 

I get where the question comes from but like Steve I don’t see anything on that panel that requires a ground.


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The 50amp relay 2622 for one.

 

Maybe, maybe not, depends how you control the relay. Switch the ground side. Don’t need a ground at the panel

I do understand what you are saying but I’m skeptical that one of those two studs is a ground, but I’ve certainly been wrong before. I would be curious to see if we ever find out for sure.


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I would love to test it but I don’t really know how to use a meter. I’ll have my dad look into it though.


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Cool, let us know what you find!


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No sweat. Pay attention to what your dad does and the meter settings that are used when he checks the circuitry. This will be a good learning experience - you'll use a meter a lot as you get further along with your build.
Keep up the good work - you'll get there.