hey guys, I'm working on putting a different wiring harness in a '79 bronco and have hit a snag. the harness came out of a truck with cruise and dual tanks and so far everything has pluged in and seems right, BUT I started connecting the harness in the engine compartment and the new harness is different than the old one. the old harness had a three prong weather pack connecter that pluged into the alternator harness and the new one doesn't have this. i'm not sure what year truck the harness came out of. will this harness still work for the truck, I'd hate to have to find another one after all the work i've put into getting this one and it is in great shape. is there a different kind of alternator harness i have to look for?

FORDS_FORLIFE

 

I would need more information to be able to answer your question.

The year of the harness you are putting into your truck is vital information. Are there any tags with part numbers on this harness anywhere? Located in the cab would be a good place to look. The tags are usually Red, have Ford on them and a part number for the harness.


Did the truck have guages, and the Bronco have idiot lights, or vice versa? There are a lot of differeces between the two harnesses, and they are not compatible without moderate/to expert wiring modifications.

 

do you know of anything on the harness itself that would tell me it's year. i bought the harness from a guy over the internet because it was a better deal than my local junkyards had. i emailed him because i don't remember if he told me the year it was from. i hope it will work, it had all the plug ins for the duraspark ignition and it seems like everything is where it should be except for the end that runs down the pass. inner fender which doesn't have this three prong rubber connector that goes to the alternator wiring harness. well except for the rear window wiring but i knew that and have seperated from the old harness and will run it seperate.

FORDS_FORLIFE

 

Look for little tags on the harness for numbers like D7TB-14197-14689.

 

well the guy emailed me back right away and it came out of a '78 F-150 supercab.

 

The harness should be the same.

Can you show me a pic of this troublesome connector ?

The connector sounds like it is for an 80's alternator.

Does yours look like this ?





THis is for a 78/79.

 

This is the connector I was talking about for the alternator harness.
https://www.ford-trucks.com/user_gal...120685&width=0

This is the alternator, external voltage regulator type, correct.
https://www.ford-trucks.com/user_gal...120686&width=0

Voltage regulator
https://www.ford-trucks.com/user_gal...120687&width=0

This is a picture of the new wiring harness. it's like it has everything the old one did except for the connector in the first picture. the weatherpack connector in this picture has two wires where as the one i'm missing has three. i think this one would plug in to the two wire connector that you can also see in the first pic.
https://www.ford-trucks.com/user_gal...120688&width=0

I you need anymore pictures let me know

FORDS_FORLIFE

 

I can't quite see from the pic how that extra connector is hooked up in the harness.

It isn't an Original Harness from what I know.

 

according to my 78 There should in fact be 2 plugs to that harness.
One with a 2 prong like you show and another with 3 prongs which you mention you don't have on this new one but do on the first image.

The wires are the key.

The two prong plug has a green/red stripe and a white/blk stripe.

The 3 prong has the large black/yellow stripe, ,a yellow,a orange

 

shoot then the guy must be wrong on its year, ill have to see if i can find a code on the harness to find out its year. the one i have just has the two prong plug. the three prong plug i have the picture of is just the alternator harness and not the main harness.

FORDS_FORLIFE

 

I cant see the pictures clearly enough to tell anything by them. But that's my web browser and not your fault.


The only thing I can think of is why they are different is that either the wiring harness is for a truck with idiot lights, and the bronco has guages or vice versa, the wiring harness is one for guages and the bronco has idiot lights.


The connector that hooks up to the voltage regulator should point that out.

On a truck with guages:

Connector #204, plugs into the voltage regulator and the colors are...

1. - circut #35 - Orange
2. - circut #904 - Green/Red stripe
3. - circut #152 - Yellow
4. - empty.

On a truck with Idiot Lights:


Connector #204, plugs into the voltage regulator and the colors are...

1. - circut #35 - Orange
2. - circut #4 - White/Black stripe
3. - circut #152 - Yellow
4. - circut #904 - Green/Red Stripe


------


And also according to the wiring diagram, there are several other major differences,

Trucks with guages have more connectors, than trucks with idiot lights.

Trucks with Idiot lights:

Circut #152 yellow wire goes from the voltage regulator to splice #203. from there the wire changes to circut #38 Black/Red stripe wire, and one wire goes to the Altenator, and the other goes to the starter solenoid.

Trucks with guages:

Circut #152 yellow wire goes from the voltage regulator to splice #202 where the wire changes to circut #38 Black/Red stripe wire, and circut #655 Red/Orange stripe wire.

Circut #655 Red/Orange stripe wire goes from splice #202 and goes to connector #206, and from there goes to the instrument cluster connector #208A and the ammeter.

Circut #38 Black/Red Stripe wire from splice #202 goes to another splice #201, where circut #37 Black/Yellow, and circut #654 Yellow/Black stripe wire split off.

From splice #201 the circut #38 Black/Red stripe wire goes to the starter solenoid.

From splice #201 the circut #37 Black/Yellow, goes to Connector #206, then leads to splice #208 where nothing splits off, and continues to splice #402, where the circut changes to #21 Yellow, and from there goes to connector #412 at the ignition switch.

From splice #201, the circut #654 yellow/black stripe wire, goes to connector #206. and from there goes to connector #208A at the instrument cluster, and the ammeter.

---------

So with all this information, the wiring harness for the idiot lights would be missing Connector #206,

And the wiring harness with the guages would have connector #206 that has three wires going into it.

1. Circut #37 Black/yellow
2. Circut #654 Yellow/Black
3. Circut #655 Red/Orange

-------

And there are yet even more differences, but I would have to write a book.

So if what I'm thinking is right, you have the wrong wiring harness, and need to get one that fits your truck, or change out your instrument cluster for the idiot light pack.

Hope this helps.

 

Oh, and just another thought.

Connector #208 is the instrument cluster connector for idiot lights.

Connector #208A is the Instrument cluster connector for guages.


They are different connectors, and I have a sneeky suspicion that if you try to connect your instrument cluster into the new harness that it wont plug in.

 

well i looked over the harness and can't find any part numbers. also the instrument cluster plugs in just fine. the bronco has full guages. not sure what you mean by the wiring for the voltage regulator, it's part of the alternator harness and not the main harness. i don't see how having guages would make a difference in the harness as the alternator still needs to connect into it. this is really starting to confuse me.

FORDS_FORLIFE

 

Wiring can be confusing, but I'll try and explain simply.

The numbers that I posted earlier are found on the FORD wiring diagram. They won't be found on your harness. I posted them so if you have a wiring diagram, you could trace the circut yourself using a diagram. Also with the numbers, you you can follow each circut easier, (at least for me) than if I just sprout off colored wires.



There are several major diferences with wiring with a truck with Idiot lights than there are with guages. Including how the altenator is hooked up to the voltage regulator.

The voltage Regulator itself turns on a idiot light by how it's wired.

and if the truck has an ammeter, the wiring for the guage is hooked into the altenator wiring, using a connector #206 on the wiring diagram.


The voltage regulator for a truck with idiot lights will have FOUR seperate wires going to it and plugging into it.

1: ORANGE
2: White/Black (Comes from the stator)
3: Yellow (this wire is doubled)
4: Green/Red

The voltage regulator for a truck with guages will have THREE seperate wires going to it and plugging into it.

1: ORANGE
2: GREEN/RED
3: Yellow (This wire is doubled)
4: This place is empty in the plug.

Notice the stator isn't hooked up to the voltage regulator, on a truck with guages,
But the stator IS hooked up to the voltage regulator for a truck with idiot lights, cause the stator wire, triggers the idiot light in the dash to turn on.

On trucks with guages, you will also note the GREEN/RED wire has swapped places from #4 to #2 and the #4 spot on the regulator is left empty.


One harness is not compatible with the other.


I still think this is your problem, but since the instrument cluster plugged in, I would say the harness to the altenator isn't the correct one now. Is this one also original or is it different too?


I will do some more research, I have Ford Bronco Diagrams as well.

 

Just checked the bronco diagram, and the altenator circuts are identical to the pickup.


You are missing a connector on one of your wiring harnesses. One with three wires in it correct?

the connector has three wires in it:

1: Yellow/Black
2: Red/Orange
3: Black/yellow

Is the colors correct? Which harness is missing this connector? The altenator harness or the Main Harness?


What color are the two wires going out to the connector for the two wire conector?

I bet they are:

1: White/Black
2: Green/Red