1973 Challenger Engine Harness Install

[Smallz118]

Hey there, 
Installing a new engine harness on a 73 Challenger with a swapped out 440 4bbl.  So far, I'm pretty confident in the placement of most of the wires.  Just a few things I have questions about, but first, here is pic of the harness I ordered from Roseville Auto (thanks guys!):



1) all right, first, where does this brown wire connect (Brown wire is on the far left of the pic)? The wiring schematic I have says it goes to the 'windshield washer,' does that make sense?



Brown wire is on the far left of the pic.

2) At the Starter Relay, the wire attached at the bottom right of the relay in this photo.  Where does that go, neutral safety switch? I don't have this in the new harness (unless it is the wire from question 1) and would therefore have to keep this section of the old harness intact, correct?



3) What the hell is this and where does it disapear to once it goes through the firewall?  Another one I assume I'll have to keep from old harness.



4) If I am correct, this is the oil pressure switch and I will hook the gray wire from the new harness into this position. Does that sound legit?



5) In the current (old) setup, there is a separate ground coming from the harness and hooked up below the ignition coil.  Is this necessary?



6) Finally, on the alternator I am going to hook up the wires from the new harness from top to bottom (or left to right in this pic) Blue, Green, then Black.  Is this correct?




I'm new to this whole thing (older vehicles and wiring in general), so any insight would help.  Thanks in advance.

Alex

[Bullitt-]

1) all right, first, where does this brown wire connect (Brown wire is on the far left of the pic)? The wiring schematic I have says it goes to the 'windshield washer,' does that make sense?

Yes, flat plug on brown wire is for the washer pump.

2) At the Starter Relay, the wire attached at the bottom right of the relay in this photo.  Where does that go, neutral safety switch? I don't have this in the new harness (unless it is the wire from question 1) and would therefore have to keep this section of the old harness intact, correct?

NSS for Automatics, Clutch switch for manual...There is a separate harness for each these. 

3) What the hell is this and where does it disapear to once it goes through the firewall?  Another one I assume I'll have to keep from old harness.

I believe that is your tachometer wire, not part of the harness, connects to the negative terminal of coil & to the tach, 

4) If I am correct, this is the oil pressure switch and I will hook the gray wire from the new harness into this position. Does that sound legit?

Correct, that is the oil pressure sending unit  Connection for Tach

5) In the current (old) setup, there is a separate ground coming from the harness and hooked up below the ignition coil.  Is this necessary?

My car does not have this wire, it does have a braided grounding strap from a LH valve cover to the firewall near the voltage regulator.

6) Finally, on the alternator I am going to hook up the wires from the new harness from top to bottom (or left to right in this pic) Blue, Green, then Black.  Is this correct?

I've read it does not matter but on my car blue is closer to the block(as in your pic on the left) & green is closer to straight up..the   different lengths of each wire in the OE harness sets it up to be that way. The large black one is the output and is held on by a nut.

[Smallz118]

Bullitt,

Great info, thanks for the quick response.  I've got most of it hooked up already, and just have to change out the ends on the alternator wires.  Otherwise, should be in good shape.  Just gotta hope this badboy starts back up!  I'll let you know how it goes.  Take it easy and thanks again.

Alex

[Smallz118]

Finished it up a few hours ago and runs great.  The tach is still unhooked, but shouldn't be too bad.  Finally got it up and running again just in time for 95 degree weather and no AC! Thanks again.

Alex

[74challenger03]

cool but were is the pic of the car?

[Bullitt-]

cool but were is the pic of the car?

http://www.cuda-challenger.com/cc/index.php?action=profile;area=showposts;u=21329

[Smallz118]

Sorry about that, did some spoiler work as well. Not great pics with the glare.



Engine bay looks like hell still. I've been troubleshooting a no-spark issue for a few weeks. I'll needto start looking into proper spark plug wire placement or purchase the brackets to help clean things up a bit. I will post some pics later. Thanks.

[EV2RTSE]

Sorry to bump an old thread, but (borrowing smallz118' picture for a moment) can anyone tell me where the plug circled in red goes?

[7212Mopar]

Looks like the plug I use for the electric choke.

[Mpdlawdog]

Nice ride!!  Love the black!  Where did you get the yellow headlights?  Im from marysville by the way...I saw you had ohio tags on the challenger

[anlauto]

My guess is tach...Where's Burdar ?

[74challenger03]

I thought gray was for tack to. yes gray -side tack. double blue chock,yellow oil sending unit.

[Bullitt-]

My guess is tach...Where's Burdar ?

I thought gray was for tack to. yes gray -side tack. double blue chock,yellow oil sending unit.

Upon further review you guys are probably correct in regards to Pic #4 above however on my '73 the gray tach wire is not part of the engine harness but runs through a grommet by itself.

So what is the circled item in the picture?

Mine has an unused spade connector that I believe was put there for technicians to use for diagnosis based on something I've read but have no documentation on that

[70chall440]

what kind of plug or terminal is it? Based on location it looks like safety neutral switch. 

[EV2RTSE]

Ok so to try to answer a few questions at once, I'm pretty sure it's not for the electric choke, as that's further up the harness (blue wires near the volt reg and ECM hookups if I'm not mistaken), and I don't believe it to be the tach because AFAIK that's the single cylindrical / round plug in one of the pictures above. The connector in question is a single, female square connector right near the bulkhead junction as circled in red my first post. My original harness has no connector here however the original wiring was repaired and possibly modified over the years. I've had the car since '89 when i first got my license in high school - first car, but back then it had some serious electrical issues so I sent it to a local diagnostic shop to have it taken care of. So it's possible this connector I'm wondering about was removed, or maybe it was never there to begin with on the original. In the years following, a lot of the other connections ended up getting spliced, many of these I did myself as the wiring got more and more brittle. After sitting for a long time I'm putting the car back on the road again, so with the repop harnesses on the market now it was finally time for a new one. I haven't unwrapped the original yet but will do that when I get a chance to look at what might have been changed by the shop - I already have the replacement M&H on the car and it's all hooked up (less the electric choke for now but that's the next step) and the car is running. My tach was working but recently quit (before I changed harnesses, and I think it's just that the gauge itself failed from old age).  As I write this, offhand I forget what all is involved with the neutral switch wiring, will have to check into that a little bit.