what is this wire for?

[mikepasquale1]

http://s1127.photobucket.com/albums/l624/firefighter1816/?action=view&current=141_0193.jpg

Bottom left of the pic, wire coming out off the top left of the firewall that is hanging straight down.

Hood light possibly?

 

[sm3570]

Mike, if no one else answers then I'll look tomorrow.

 

[OLE PONY]

My 73 does not have it. Mine does not have air conditioning so I'm thinking it's for air conditioning, but not sure. The hood light runs across the top of the passenger side shock tower brace.

 

[will e]

You are talking about the one that hangs from the top of the firewall and has a connector on the end?

 

[Detector]

Well looks like I'm no help. Mine is cut.

 

[will e]

It's either for the tach or for the alternator/guage option. I remember when I swapped in the guage package 20 years ago I had to pull it from the one car and put it in the other.


looking at my old wiring diagrams I am pretty sure it is for the charging circuit when you have an amp meter. It goes to the amp guage inside and has a connector as part of the charging circuit in the engine bay side.

 

[rvrtrash]

I would guess it's for the EGR cutout solenoid. It's a small vac solenoid that mounts to the right rear of the intake and controls vacumn to the EGR valve, via the EGR control module (if I guessed right and read the schematic correctly). I replaced my intake and ditched the EGR valve, but still have the original pieces, and that looks like where it goes.

Steve

 

[OLE PONY]

This question and picture would have made a great weekly fun question!

 

[will e]

what color is the wire?

 

[73vertproject]

Not sure if this will help, but I labeled mine "wiring harness". It's black, fused to a black wire with red/pink stripe.

 

[goodnigh]

My March made '71 does not have one but it did come with A/C.

mike

 

[midlife]

It's either for the tach or for the alternator/guage option. I remember when I swapped in the guage package 20 years ago I had to pull it from the one car and put it in the other.


looking at my old wiring diagrams I am pretty sure it is for the charging circuit when you have an amp meter. It goes to the amp guage inside and has a connector as part of the charging circuit in the engine bay side.

Not tach or ammeter related: both systems are part of the main headlight harness.

 

[mikepasquale1]

Ya i had my doubts about that as well. The ammeter and tach are part of the main headlight harness. THis is something different. Ill get you a color ASAP. If memory serves, its brown with yellow dotted striping but let me double check. i have a few diagrams and i cant pinpoint it. The EGR or A/C selonoid do make sense. Ill get some more indepth info on the wire color. The pic i posted was the before picture, as you can see i have a few things in my way now for a good line of sight at it lol.

 

[will e]

The amp light goes through the main headlight harness but I 'believe' that when an actual AMP guage is used they had to use a larger wire (even though it is shunted) because it has to handle the actual charge/discharge load (or at least half of it). But I have been wrong about these things.

 

[midlife]

The amp light goes through the main headlight harness but I 'believe' that when an actual AMP guage is used they had to use a larger wire (even though it is shunted) because it has to handle the actual charge/discharge load (or at least half of it). But I have been wrong about these things.

It does, but it is still within the headlight harness. The tach/amp version has two large wires that connect to the starter solenoid or a junction block: one for the main power (fusible link) and another for the ammeter shunt.

 

[will e]

Interesting. I will check my old schmatics. I took careful notes when I swapped out the non-guage package to the tach/amp/water/oil setup.

Well, okay, maybe not 'that careful'. I was 20 at the time. I still remember sitting in my parents driveway. I had the dash apart. I didn't want to splice any wires so I pulled each of them out of the connectors. I thought to myself. Hey, start it up before you bolt it all back together and the car wouldn't turn over. Long story short... the solinoid had given up on me during the conversion. But I paniced when I thought I had just hosed up my 'new' car.

 

[Jeff73Mach1]

I may have an answer

The AC idle solenoid grounds thru the engine and used a plug that looked like that on my 1972 Maverick (which I sold 30 years ago). I think that is what you have and if it has power when the AC is switched on and not otherwise, you may have your answer. I thought it came through with the main harness, but if a car had dealer installed air, it might well be right there.

 

[mikepasquale1]

Yupp i think thats the conclusion i came to as well. Thanks man