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Dash wiring questions

K

Kats66Pny

Active Member
I took down the diamond plate dash, and there's tons of wires back there.. as well as a rotted @$$ cowl vent that looks like it's about to fall off. :ep
But back to the wires, it looks as if the PO didn't hack it up too much back there.

I have noticed two things.

#1. The current oil pressure gauge/sending unit. I didn't see an individual sending unit. Only the gauge itself. There's a steel line going from the engine through the firewall and from that a smaller steel line that connects directly to the gauge. And there's some oil leaking (not a lot, but wires are a little oily) from the back of the gauge. This is an aftermarket cheapo gauge from Auto Zone (I recognized it on the shelf before). Is this some sort of combo gauge/sending unit?

I guess either way I'm going to have to figure out a way to put on the unit that came with the dash.


#2. There's no speedometer cable. :sad After several google searches I was able to figure out where it's suppose to be going through the firewall and nada. Just the hole there. My question about that is can I just go to an auto parts store and get any cable or do I specifically need one for a 66 mustang w/a 302?
 
Kat,

first, that aftermarket guage is a manual guage, not electric. it reads direct pressure thru the tube therefore doesn't need a sending unit. i would think on the speedo cable you would be better off ordering the correct one from a mustang supplier. wouldn't think the reg parts houses would have one in stock that would work on an older car. you might think about sending that dash harness to midlife for an overhaul. if you send him that pic, you might get a discount :lol
 
first, that aftermarket guage is a manual guage, not electric. it reads direct pressure thru the tube therefore doesn't need a sending unit.
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Ahh ok. That makes sense.


i would think on the speedo cable you would be better off ordering the correct one from a mustang supplier. wouldn't think the reg parts houses would have one in stock that would work on an older car.
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I checked a few places online and O'Reillys had a 60" Pioneer Inc (Part Number: CA3015) speedo cable for 1955-1984 AMC/Ford/Ford Truck/Lincoln/Mercury vehicles. I suppose that would work?


you might think about sending that dash harness to midlife for an overhaul. if you send him that pic, you might get a discount
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Hmm. :lol :lol :lol
 
The stock sending unit screws into an aluminum hex shaped tube that screws into the block just to the rear of the stock fuel pump location. This can be found on several later years of Fords if you look thru a salvage yard. I found on on a early '80s Ford F150 with a V8. Cost me $5.

As for the wiring, does it feel brittle like the insulation will crack when it is bent or does it look fairly new and clean? Pull the wiring out from the dash a bit and start sorting out what is there. Maybe a couple of pics posted and we can give more guidance.

Not sure of the length of the stock speedo cable but those should work as long as you make long loops. What does the car have in the speedometer hole on the transmission? Should be almost to the end of the back section (tail shaft) of the transmission, located at about an 11 o'clock position,,,,,,a bit high on the side. You may need a speedo gear also as that is what goes into that hole to turn the inner cable.
 
I snagged this picture from Kevin's oil leak thread. Visible on the right side of the photo is the oil pressure sending unit connected to an extension shaft and then screwed into the side of the engine block. This is a stock configuration that uses an electrical sending unit connected to a wire that operates the instrument cluster gauge. The water temp gauge will operate in similar fashion.... sending unit screwed into intake water jacket... connected to wire on the engine harness.... that provides signal to the instrument cluster gauge.

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You can buy a speedo cable directly from Autozone/O'Reily's, but it's a generic one and it might be a few inches longer than neccessary. 54 inches should be a good length.

Like Pete said, I'm real curious what's going on with the speedo port on the side of the transmission. Without a cable it should be leaking tranny fluid at a pretty high rate. I suppose it could be plugged.
 
I have no idea whats in the speedo hole on the trans. I'll have to go check that. I'll try to get some pictures as well of the wiring.
 
"SELLERSRODSHOP" said:
Kat,

first, that aftermarket guage is a manual guage, not electric. it reads direct pressure thru the tube therefore doesn't need a sending unit. i would think on the speedo cable you would be better off ordering the correct one from a mustang supplier. wouldn't think the reg parts houses would have one in stock that would work on an older car. you might think about sending that dash harness to midlife for an overhaul. if you send him that pic, you might get a discount :lol
Click to expand...

"Kats66Pny" said:
I have no idea whats in the speedo hole on the trans. I'll have to go check that. I'll try to get some pictures as well of the wiring.
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I don't think he was speaking of the picture of the wiring Kat. :naug
 
:lol

Here's a few pictures.

In the first picture you can see that the fuel line connects from the area where the stock oil sending unit is suppose to be and goes up over the valve cover and into the firewall.
I'm going to guess that I'm going to have to redo that.

Second picture, according to this diagram - http://hammar.dyndns.org/~djhamma/wiring/1966/66inter.jpg that cut off wire was suppose to connect to the temp and oil sending units.
How the heck am I suppose to fix that? New harness all together? Splice new wires on to it and wrap that sucker in electrical tape?[nb]FYI when I say me, I mean with assistance from hubby since he worked with electronics in the Marines and knows about electrical stuff.[/nb]

Third pic, I can't seem to get a good picture of the harness back there because of steering wheel, but you can make out some of it. Some of it looks to be original wiring that the PO cut the end and caps off and added connectors to make it fit the aftermarket gauges.
 
The first pic....looks like a hard line for the oil pressure gauge (verify by checking other end) running to inside the car. Remove and install the aluminum as pictured before.

The second picture....those ends can be spliced and maybe sourced from Midlife or purchase new gauge harness.

Third pic.....remove the old cluster, pull the steering wheel and dive in. No other way but I will say there is plenty of help on here that we all can talk you thru any issues you cannot sort out.

Does hubby have some GOOD wire splicing equipment.....
 
"AzPete" said:
The first pic....looks like a hard line for the oil pressure gauge (verify by checking other end) running to inside the car. Remove and install the aluminum as pictured before.
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It's a hard line all the way to the back of the aftermarket oil gauge.


Does hubby have some GOOD wire splicing equipment.....
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I believe he does.
 
Something else I forgot to ask about. The numbers on the odometer. Do I just leave it sitting at what it is? I'd ask about changing the numbers but isn't it illegal to change odometer numbers? I don't even know how many miles are even on this car/engine anyway.
 
Check your title and see what it says for mileage. Some say exempt, beyond the limits of the unit or something like that. I just installed the new one in mine and started at 0. You can take that one apart and set it where ever you want.
 
A long time ago, when I put in the 351W engine, I rolled back the odometer to 0. that way I would know what the mileage on the motor was. To me, that was more important than what was on the chassis. I don't even know if the odometer had been rolled over once/twice. If you ever sell the car you just have to state that the reading on the odometer is not the actual mileage on the car. What's illegal is if you represent the car as having fewer miles on it that what actually are. At least here in CA, there's a check box on the title when transferring that states, the mileage on the odometer is not the actual mileage. Since then I went to an Autometer speedo, so I started over at zero again...which coincides when I put efi on the car.

It's been awhile, but IIRC, it's pretty simple to zero out the odometer.
 
2nd pic: yes, that is the oil sending, temperature sending, and coil lines that have been cut off. You'll need a new gauge harness (cheap).
3rd pic: I see yellow vinyl tape and a number of splicings. Ugh...


My, what pretty hands you have!
 
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