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9/12/2020 2:25 PM  #1


I have decided to change my custom wiring harness around. 1966 289 cou

I have a new under dash harness made.  I cant decide how I want to run my exterior light, turn signal feed, horn, fog lights,and my choke and alternator relays. For my choke and alternator relay im thinking of drilling a hole in the firewall to the side of the dimple directly behind the intake. That would give me a straight shot to the carb and then I can just run my 3G alternator wiring green/red  straight to it. The exterior portion of the harness im at a loss I have it in place now but I dont like it. Plus the way I have it going into a 6 fuse 6 relay box located under the battery on the inner fender portion.. at first I had all my wiring ran in the passenger inner fender. Now im not sure if I care for it.  I cant buy replacement wiring connectors for this relay box I have to make it work. So I either have to buy replacement or do some rewiring. Thats why im second guessing how I have done the job. Any insight ideas are much appreciated.

 

9/12/2020 2:57 PM  #2


Re: I have decided to change my custom wiring harness around. 1966 289 cou







I also have a few extra relay sockets and extra wire so I can easily rewire the exterior wiring


     Thread Starter
 

9/12/2020 3:05 PM  #3


Re: I have decided to change my custom wiring harness around. 1966 289 cou

I should add that I do plan on upgrading my current radiator to a larger 24"  radiator. And I was planning on installing a 67 mustang battery tray.

     Thread Starter
 

9/15/2020 12:33 AM  #4


Re: I have decided to change my custom wiring harness around. 1966 289 cou

It’s such a major undertaking to rewire a car. Are you starting from scratch by copying what Ford did, making use of a factory type harness, or customizing some one’s kit? I find making sketches of what I intend to do helps a lot. It creates a plan that I can come back to if I walk away for a week or two. I still have to relearn where I was, but ht etime I spend scratching my head wondering what the hell I was thinking is cut way down.  
 
For me, I was looking to have the wiring routed around the car with as few paths possible for wire coming from the car onto the motor, if that makes sense. I have 3 places…back of the intake, across the valve cover for distributor and at the alternator.  I used a Painless kit on my 67 and routed it through the car following the same path Ford did. It’s what made the most sense for me. So… the front exterior lighting, brake switch, wires for alternator to what would have been a voltage regulator, low pressure switch for the AC, starter solenoid, and horn all enter the engine compartment on the driver side following the apron to the core support. It passed through the core support down low went across the front and back through the core support to the solenoid and alternator. The headlight relays are up high on the driver side apron. Head lights and turn signals are dropped off at the front corners, the two wires for the voltage regulator were extended around to the alternator and starter relay, I think….it’s been a few days!!
 
The factory oil pressure switch & water temperature, an Autometer oil pressure & water temperature, AC compressor power, choke, and reverse lights all come from the area you are talking about. The spark box for the Duraspark is mounted midway on the Apron on the driver’s side with wiring routed across the valve cover to the coil and distributor. It makes for a nice clean installation. I do have 4 fuse blocks mounted below the starter solenoid. There is a main fuse from the alternator, one for the Painless harness fuse block, one for the auxiliary fuse block, and the last is for the amp. It makes for a nice clean installation.
 
The power cable for the trunk mounted amp runs in the fender well on the passenger side. It was a good path for easy access to the interior. What is not appealing to you about that route now? I see your relays look like someone crimped those ends onto them before loading into the plastic housings. With a little patience and the right tool, they can be removed to make changes. If all else fails, but splices and heat shrink to make changes. I am curious….why do you need a relay for the alternator and choke?
 
How do you intend to fuse all of the loads? I see one fuse mounted on the apron below the starter solenoid.


I will try to get my pictures updated in the build section for My Cars. It might help. 


John  -- 67 Mustang Coupe 390 5 speed
 

9/15/2020 5:12 PM  #5


Re: I have decided to change my custom wiring harness around. 1966 289 cou

I do not have any stock wiring in my car. I Decided to build all my wiring from scratch. I used all factory color wiring plus some extras. The fuse boxes under the dash are 4 gang delphi which can be interlocked with additional fuse boxes or interlocking relay housings. They are nice and you can get them for cheap on Rockauto.com. For the alternator I upgraded to a 3g alternator I needed to install the 560 ohm 1/2watt resistor plus I wanted the dummy light to function but using an LED instead of the standard incandescent. I was informed that a relay would be my only way to get the alternator and dummy light to function. The electric choke relay is just because I dont want to put a load on the ignition switch.
The one fuse you see below the fender solenoid powers my alternator as well as my tyco relay that powers my under dash harness.

Last edited by True74yamaha (1/07/2021 11:29 PM)

     Thread Starter
 

9/15/2020 5:45 PM  #6


Re: I have decided to change my custom wiring harness around. 1966 289 cou

I know BB is using a led as a charge light. Pretty sure his fix involved a relay as well.


"Those telephone poles were like a picket fence"
 

9/15/2020 9:27 PM  #7


Re: I have decided to change my custom wiring harness around. 1966 289 cou

My hats off to you, I had no desire to build my own harness. Making modifications to the Painless one was pain full enough. Bullet Bobs guide to wiring provided me with part numbers to a fuse block that is similar to what you are describing and they have worked great so far.
 
I added the 3G with a resistor for the idiot light as well. I kept the typical incandescent bulb….so no relay for me. It works great, in fact, it given less trouble than the motor!!! My understanding with the incandescent was the filament allowed current to pass through to activate the exciter signal to the alternator so it created voltage. The resistor is added to allow this process to still take place if the bulb burns out and breaks the circuit. You guys probable have it right….I’ve never thought about how an LED would change things. It seems like here would still be some type of internal transformer that would pass the current.
 
I can understand not wanting to add any load to the ignition switch. Have you thought about using a 40 or 50 A relay with the relay coil powered by the ignition switch to power up some of your fuse blocks? You keep the fuses in place and need fewer relays, maybe. Just a thought, I haven’t seen under the dash.  
 
From looking at the pictures, where is the fuse located in relation to the alternator, battery, and fuse block? It’s hard to tell. I placed the main fuse within a foot of the alternator. If anything downstream shorts or overloads, it should pop the fuse. 


John  -- 67 Mustang Coupe 390 5 speed
 

9/15/2020 11:35 PM  #8


Re: I have decided to change my custom wiring harness around. 1966 289 cou

50vert wrote:

I know BB is using a led as a charge light. Pretty sure his fix involved a relay as well.

Thank you I forgot to mention BB helped me out with the Alt/Dummy light, and electric choke relay wiring. Thanks again BB.

Last edited by True74yamaha (9/16/2020 12:02 AM)

     Thread Starter
 

9/16/2020 2:19 AM  #9


Re: I have decided to change my custom wiring harness around. 1966 289 cou

True74yamaha wrote:

50vert wrote:

I know BB is using a led as a charge light. Pretty sure his fix involved a relay as well.

Thank you I forgot to mention BB helped me out with the Alt/Dummy light, and electric choke relay wiring. Thanks again BB.

Yeah ... he's strange that way.
And now you know it's done right.
 


"Those telephone poles were like a picket fence"
 

9/18/2020 4:45 PM  #10


Re: I have decided to change my custom wiring harness around. 1966 289 cou

I used these fuse fuse boxes, they are the best price on rock auto. They are interlocking so you can also mount some interlocking relays on them as well as multiple fuse blocks. 



     Thread Starter
 

10/24/2020 2:53 PM  #11


Re: I have decided to change my custom wiring harness around. 1966 289 cou

I ended up deciding instead of drilling a hole in the firewall for my wiring, i fscored both the under dash firewall wiring connectors. I plan on splicing these into my new under dash wiring harness this way I dont have to patch the stock holes. Plus this way I can alway order a replacement engine gauge feed or exterior light harness and it will be an almost plug and play install.

     Thread Starter
 

10/24/2020 3:17 PM  #12


Re: I have decided to change my custom wiring harness around. 1966 289 cou



I purchased theses off ebay I plan on either splicing these into my harness or drilling out the old bulletts and using epoxy to install new bullett connectors.

     Thread Starter
 

12/08/2020 2:48 PM  #13


Re: I have decided to change my custom wiring harness around. 1966 289 cou

The reason why I went with the bottom picture (63 falcon part) for my engine feed is because it has two extra wiring connections. I plan on using the extra green for my electric choke and the green red stripe wire for my 3g alternator. On picture on the top its a 1965 mustang exterior light underdash plug. I was curious since I have a 80amp relay under my dash. I was curious do I have to run the #37 black yellow to the fender solenoid or can i just hook it up to the relay? 

     Thread Starter
 

12/08/2020 10:30 PM  #14


Re: I have decided to change my custom wiring harness around. 1966 289 cou

Probably not.  37 is the "always hot" cabin power to the Ign switch, headlight switch, brake light switch, cigar lighter and E-flasher.  Ford never protected it but it's not a bad idea to install a fuse near the solenoid to protect it.  Fuse size will depend on what you have hanging off of it.  If you have relay switched headlights and accessory sources you can probably get away with 25A or so.

Edit:  You could connect 37 to the source terminal of that relay as long as it's always hot.  Be sure the source for that relay is proceted and I recommend you indiviually protect all the circuits off of that relay.

Last edited by Bullet Bob (12/08/2020 10:34 PM)


"you get what you pay for, good work isn't cheap, and there are NO free lunches...PERIOD!"
 

12/09/2020 12:02 AM  #15


Re: I have decided to change my custom wiring harness around. 1966 289 cou

Thanks Bob for pointing this out,
I question that you said the cigar lighter is alway hot. On my 65 there is a 20a fuse in the stock block that say lighter. have I missed something? I too have been rewiring my car and now will add a fuse to #37 wire at the battery end.
My car is now LED front and rear so that amp draw is somewhat lower, but as for the ing sw Im not sure, guessing everything on the fuse block except the cig.  so I will do a amp draw and fuse #37 accordingly. 
As of 11:30PM I have installed a AGU type fuse holder with a 50a fuse. I will be able to incress or decress if needed. I dont want any non fused wires.

Last edited by Cab4word67 (12/09/2020 1:48 AM)


Slammed Big Blue, ran over the varmints that messed with the Stang. Now all is good in the NW
 

12/09/2020 7:55 AM  #16


Re: I have decided to change my custom wiring harness around. 1966 289 cou

I admit I'm not that familiar with the 65, Chris, and they are different.  The 66 used one ckt for the cigar lighter and the E-flasher.  I can't recall if it was fused, I threw the original fuse box away and made my own.  Cigar lighter became a separate "always hot" power point ckt...one of four in the car. 


"you get what you pay for, good work isn't cheap, and there are NO free lunches...PERIOD!"
 

12/09/2020 8:26 AM  #17


Re: I have decided to change my custom wiring harness around. 1966 289 cou

Bullet Bob wrote:

Probably not.  37 is the "always hot" cabin power to the Ign switch, headlight switch, brake light switch, cigar lighter and E-flasher.  Ford never protected it but it's not a bad idea to install a fuse near the solenoid to protect it.  Fuse size will depend on what you have hanging off of it.  If you have relay switched headlights and accessory sources you can probably get away with 25A or so.

Edit:  You could connect 37 to the source terminal of that relay as long as it's always hot.  Be sure the source for that relay is proceted and I recommend you indiviually protect all the circuits off of that relay.

I was debating fusing and hooking up the #37 to my Tyco 200amp relay that I have mounted to a panel under the dash.
It also feeds some other hots as well as my fuse box. I was thinking this would look kinda neat so that I dont have to run just the one black/yellow #37 all the way to the fender solenoid.

     Thread Starter
 

12/09/2020 8:28 AM  #18


Re: I have decided to change my custom wiring harness around. 1966 289 cou

Cab4word67 wrote:

Thanks Bob for pointing this out,
I question that you said the cigar lighter is alway hot. On my 65 there is a 20a fuse in the stock block that say lighter. have I missed something? I too have been rewiring my car and now will add a fuse to #37 wire at the battery end.
My car is now LED front and rear so that amp draw is somewhat lower, but as for the ing sw Im not sure, guessing everything on the fuse block except the cig.  so I will do a amp draw and fuse #37 accordingly. 
As of 11:30PM I have installed a AGU type fuse holder with a 50a fuse. I will be able to incress or decress if needed. I dont want any non fused wires.

How do you like the auto cool guy controller? Im pretty sure that will be my next modification along with a larger radiator for my 1965 mustang coupe. 

     Thread Starter
 

12/09/2020 12:12 PM  #19


Re: I have decided to change my custom wiring harness around. 1966 289 cou

True74yamaha wrote:

Cab4word67 wrote:

Thanks Bob for pointing this out,
I question that you said the cigar lighter is alway hot. On my 65 there is a 20a fuse in the stock block that say lighter. have I missed something? I too have been rewiring my car and now will add a fuse to #37 wire at the battery end.
My car is now LED front and rear so that amp draw is somewhat lower, but as for the ing sw Im not sure, guessing everything on the fuse block except the cig.  so I will do a amp draw and fuse #37 accordingly. 
As of 11:30PM I have installed a AGU type fuse holder with a 50a fuse. I will be able to incress or decress if needed. I dont want any non fused wires.

How do you like the auto cool guy controller? Im pretty sure that will be my next modification along with a larger radiator for my 1965 mustang coupe. 

ture74Yamaha,
I like it I am running a stock size American Eagle alum rad with 2 rows of 1" tubes. I have AC and have fought some cooling issues but feel I got it all under control now. My old motor was some of it Im sure. I did a mod to the core suport to move the rad up closer to the front of the car so it is almost touching the AC condenser so that should help air flow. That also gave me some more room from the water pump. I have a cheap Derali fan pulling and the Autocoolguy is almost at max but kept the car cool stuck in a 1 hour plus jam at 85 deg with the AC on. I think that after i get my motor back I will replace the fan with a better one now that I have more clearance. moving air is the key as the controller just keeps it all working without relays to fail. The autocoolguy controler reads the hot water going back to the engine witch is better I think.  
I would have done the bigger rad but I was yonger and not as well educated then. And think the dual cross flow dezine would be a good choise.
Chris

Last edited by Cab4word67 (12/09/2020 6:50 PM)


Slammed Big Blue, ran over the varmints that messed with the Stang. Now all is good in the NW
 

12/12/2020 4:56 PM  #20


Re: I have decided to change my custom wiring harness around. 1966 289 cou

True74yamaha wrote:

I am curious….why do you need a relay for the alternator and choke?

FYI - I don't have a relay for my Holley Electric choke, I have a 3amp fuse that powers the choke, tachometer (an early 70's Sun unit) and the feed for the Dakota Digital electronic antenna.  I have had no problems with this setup.

My winter project is moving the battery to the trunk, and re-wiring portions of the car.  I decided to use the "Racer Inc" WB-14 wiring panel that incudes fuses, relays and flashers, but no external wires.  I'm mounting the panel in the glove box, which is an ABS plastic unit that came with the Vintage A/C system.
 


65 Fastback, 351W, 5-speed, 4 wheel discs, 9" rear,  R&C Front End.
 

12/12/2020 6:31 PM  #21


Re: I have decided to change my custom wiring harness around. 1966 289 cou

Hum thats a great Idea there Bob. I have thought about putting my stereo deck from the trunk and the new fuse box in there. Just incase I want to look at the deck. Wonder if I kept that thing from Vintage Air


Slammed Big Blue, ran over the varmints that messed with the Stang. Now all is good in the NW
 

12/12/2020 7:15 PM  #22


Re: I have decided to change my custom wiring harness around. 1966 289 cou

BobE wrote:

  I'm mounting the panel in the glove box, which is an ABS plastic unit that came with the Vintage A/C system.
 

Might as well use it for the fuse panel, it useless as a glove box.  One of these days I'm going to make patterns and produce a few of my five-piece plastic glove boxes...see if anyone is interested.  Mine allows the Gen IV HVAC system but is easily installed and is only 1 1/2 inches shallower than stock...leaves plenty of room to be called a "glove box".
Some day......


"you get what you pay for, good work isn't cheap, and there are NO free lunches...PERIOD!"
 

12/12/2020 8:01 PM  #23


Re: I have decided to change my custom wiring harness around. 1966 289 cou

Bullet Bob wrote:

BobE wrote:

  I'm mounting the panel in the glove box, which is an ABS plastic unit that came with the Vintage A/C system.
 

Might as well use it for the fuse panel, it useless as a glove box.  One of these days I'm going to make patterns and produce a few of my five-piece plastic glove boxes...see if anyone is interested.  Mine allows the Gen IV HVAC system but is easily installed and is only 1 1/2 inches shallower than stock...leaves plenty of room to be called a "glove box".
Some day......

Some day. Is that like a round to it?


Gary Zilik - Pine Junction, Colorado - 67 Coupe, 289-4V, T5
 

12/13/2020 12:32 AM  #24


Re: I have decided to change my custom wiring harness around. 1966 289 cou

Cab4word67 wrote:

True74yamaha wrote:

Cab4word67 wrote:

Thanks Bob for pointing this out,
I question that you said the cigar lighter is alway hot. On my 65 there is a 20a fuse in the stock block that say lighter. have I missed something? I too have been rewiring my car and now will add a fuse to #37 wire at the battery end.
My car is now LED front and rear so that amp draw is somewhat lower, but as for the ing sw Im not sure, guessing everything on the fuse block except the cig.  so I will do a amp draw and fuse #37 accordingly. 
As of 11:30PM I have installed a AGU type fuse holder with a 50a fuse. I will be able to incress or decress if needed. I dont want any non fused wires.

How do you like the auto cool guy controller? Im pretty sure that will be my next modification along with a larger radiator for my 1965 mustang coupe. 

ture74Yamaha,
I like it I am running a stock size American Eagle alum rad with 2 rows of 1" tubes. I have AC and have fought some cooling issues but feel I got it all under control now. My old motor was some of it Im sure. I did a mod to the core suport to move the rad up closer to the front of the car so it is almost touching the AC condenser so that should help air flow. That also gave me some more room from the water pump. I have a cheap Derali fan pulling and the Autocoolguy is almost at max but kept the car cool stuck in a 1 hour plus jam at 85 deg with the AC on. I think that after i get my motor back I will replace the fan with a better one now that I have more clearance. moving air is the key as the controller just keeps it all working without relays to fail. The autocoolguy controler reads the hot water going back to the engine witch is better I think.  
I would have done the bigger rad but I was yonger and not as well educated then. And think the dual cross flow dezine would be a good choise.
Chris

Awesome thanks a lot.

     Thread Starter
 

12/13/2020 12:36 AM  #25


Re: I have decided to change my custom wiring harness around. 1966 289 cou

Bullet Bob wrote:

BobE wrote:

  I'm mounting the panel in the glove box, which is an ABS plastic unit that came with the Vintage A/C system.
 

Might as well use it for the fuse panel, it useless as a glove box.  One of these days I'm going to make patterns and produce a few of my five-piece plastic glove boxes...see if anyone is interested.  Mine allows the Gen IV HVAC system but is easily installed and is only 1 1/2 inches shallower than stock...leaves plenty of room to be called a "glove box".
Some day......

Sounds like a neat lil box. Very interested for in the future.

     Thread Starter
 

Board footera


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