1964 to 1965 Mustang wiring harness conversion discoveries.
Well the firewall pad and heater went in so well I thought I'd start on the underdash harness. Let's just say we'll wait at least another week before we claim victory on that one...
I did, however, make a few discoveries. The '64 harness, at least on this car, has the windshield wiper harness integral to the underdash harness. This is not the case with the '65. My new '65 harness has a bullet connector (orange/white) for the wiper switch/motor harness, but the wiring itself is separate, and by the way not available aftermarket (or at not that I could find); no problem I thought, as I had an old one from a harness I bought on e-bay years ago. Discovery two: That new '65 wiper harness doesn't fit on either the switch or the motor of the '64. I'm now in the process of separating the wiring from the '64 harness for inclusion on the new '65. Of course since it wasn't separate in '64 it doesn't have the connector needed (discovery #3)... Anyone have a source for the proper size bullet connectors, for these harnesses?
Still think you should have bought the 66 wiring. Try Radio Shack or check the Yellow Pages for a company that specializes in electrical supplies. Darned, I still think you should have bought the other harness,LOL All the best, Chuck
I found the connectors at a new NAPA store. Radio shack, AA, AZ, only had the smaller ones.
I looked hard at the '66 but the '65 seemed to allow me to use most of my existing '64 connections. So far the wiper harness is the only mismatch... Of course it's early yet.
This weekend saw the installation of the underdash harness, taillight harness, turn signal wiring, steering column, and assorted underdash items which came out as a result of the harnesses... So far, so good. Of course I haven't put power to it yet.
Hopefully, next weekend will be connection of the taillight and turn signal wiring under the dash, and the installation of the engine compartment harnesses.
Also, my modified '64 wiper harness fits well; time will tell if it actually works...
Is there an aftermarket source for the 6-pin connector, for the turn signal switch, that would mate to the female connector of the underdash harness? The new underdash comes with a connector for the turnsignal wiring, but the new switch wiring has loose bullet type connectors. These do not fit securely, and have a lot of area exposed once connected; which seem to me to be potential shorts.
If nothing is available I plan to use heat shrink on each and then tape, but I'd much rather have a connector.
Went the route of trying to use two new connectors, replacing the one on the U/D harness. I used a pin removal tool to free the pins from the existing 6-pin connector housing. I'd hoped to be able to insert the existing pins from both harnesses into the two new, male and female, plastic housings. No luck.
My intent is to avoid having to cut, trim, crimp, and connect in the very limited underdash space...
New discovery: Pins come in different sizes. The two new connectors have pins which are a different size than the existing. These existing pins are too small for the .93 size I bought from Radio Shack.
Next step is to find an "electronics" store with a wider selection, and hopefully someone who knows about electronics, and buy new connectors which are the proper size for those existing pins...
Lesson learned at this stage: check all connections, and replace as needed, before installing...
I have a question? Are you trying to place a 65' harness into a 64 1/2 or the other way around. As if I remember correctly the 2 speed wiper as an option in the 1964 1/2 and a single speed was standard and they may have made the 2 speed standard in 1965 which would explain they differences. As far as the connectors they are of the same size as trailer connectors and some places sell them as 2 terminal thru 6 terminal if I remember correctly. If I can remember where I got them from the last time I will post it.
I found the new connectors and was able to use the existing pins. I was concerned about making good contact because I had been messing around with those pins so much over the last week or so. I did a continuity check from end, to end, of each circuit and things seem fine.
I understand that they can't attach the connector housing because the new turnsignal switch wiring must pass the steering column channel, but I don't know why they can't include the plastic housing for later...
Here we go again after the short detour for brakes. Already today I've had to ask clarification on horns differences between '64 and '65; there's more...
When the 351w was installed and the previous owner converted to electronic ignition, he spliced all his wiring. Knowing this I shouldn't be surprised when I find that connectors on the new '65 harness aren't where the existing ones are.
Where does the '65 voltage regulator usually reside? My car has it next to the starter relay, alternator side. However, the new '65 harness has the connector on the left side of the car, near the old horn relay.
Can someone show / tell me where it should mount (does it matter as long as it connects)?
Today I tried to install the alternator harness. It came as no surprise that the old harness is completely different. Below are old and new (on alt).
Can anyone tell me if my connection is correct? The only markings on the alternator are "BAT" and "GRD"; those are easy. The two I'd like to confirm are the "White" and "White w/black" wires.
All harnesses are in; to include the new "Painless" duraspark harness. I started the car and noticed that the starter would not disengage, and the ignition switch would not turn off the engine. I ended up disconnecting the "white" duraspark wire (runs between module and the "S" terminal of the relay" This fixed both problems...
The white wire is supposed to retard timing at startup, and is not critical beyond that. That being said I still want to know why it doesn't work correctly.
I tested the wire (disconnected from the relay) and it has voltage coming from the module (not supposed to). The assumption is that the module is malfunctioning.
Attached is the wiring diagram of what I have. Does any one have an idea on what went wrong?
Well I think I'm done with this one. I ended up putting a diode in the white wire to prevent the voltage from the module to the relay. I still have no idea why that's happening, but it seems to work. I can't swear that the engine retards as it should, but if anyone has a test procedure for that I'd gladly test it...
The engine starts and runs great. I also changed cap, wires, and plugs. Initial timing is set at 12 BTDC. One additional change; I mentioned to the parts guy that the old plugs showed it had been running rich, and he suggested Autolite 26's instead of 25. I'm assuming that's a hotter plug. I wasn't sure of the gap so I left them at the .42 they came with.
1964 to 1965 Mustang wiring harness conversion discoveries. 
