Wire Harness removal

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Joined
Dec 10, 2017
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Location
Georgia
My Car
1973 Mach 1 "Q Code"
I am in the process of cleaning up my engine compartment, rust prevention and painting and have taken the engine wire harness loose and want to remove it completely so that I can hopefully send off to Midlife for refurbishing soon. From what I see, it goes through the firewall grommet, is there a disconnect located somewhere? If not, what are the recommendations to remove the harness? Are the engine, interior/dash and rear harnesses actually one harness or separate? Thanks and I appreciate any advice and assistance.

Tom

 
The big headlight harness plugs into the back of the fuse box. Loosen the bolt on the front of the fuse box, but it is captured so it won't come completely out. When it is free, you should be able to pull the fuse box away from the connector of the headlight harness (square green connector). Carefully push the two locking tabs holding the headlight harness connector into the metal frame, and push out from the metal frame. The headlight harness is removed by pushing the grommet into the passenger compartment, and the rest has to follow.

Down along the driver's side kick panel, you'll see two square connectors (one red, one white) that connect the rear tail-light to the underdash harness.

Don't forget: NOT to cut any wires while removing the harnesses!

 
Here are a couple pictures of what Midlife is talking about. +++ on not cutting wires, everything will come out with connectors in place.

It is easier to take the whole dash to work on the harness under the dash. Only couple bolts on top one on each side after the dash pad comes off. The two at the bottom each side where the L brackets are and there is a brace rod on the left side of the glove box. Then once the steering column is out of the way there is a bolt right over the steering column. Then you can remove the whole dash after unplugging any connections in the A pillars and some to heater that stay on the firewall.







 
+2 On the previous posts. As you can see in the pictures the harness runs thru a plastic tube behind the dash gauges which is hard to get to without partially disassembling the dash.

Also, you did not say what model or options you have. If you have a convertible and/or power windows, or the convenience group option (things like seatback release actuators, hood and trunk lights) you will have a second wire harness running from inside the driver's side kick panel thru the firewall and along the engine compartment firewall to the starter solenoid. Then you may want to pull this harness while you have it apart and send it to midlife as well.



 
Thanks all, I appreciate the advice and assistance. Hopefully weather will be good this weekend and I will be able to do some work on it this weekend and see what all I have to remove to get this harness out. BTW it is a 73 Mach 1, Q Code, no engine installed at this time. Luckily, the only wires that I have seen cut is one that looks like it would go somewhere around the drivers seat. No clue yet what that was but will do some investigating.

Tom

 
Thanks all, I appreciate the advice and assistance. Hopefully weather will be good this weekend and I will be able to do some work on it this weekend and see what all I have to remove to get this harness out. BTW it is a 73 Mach 1, Q Code, no engine installed at this time. Luckily, the only wires that I have seen cut is one that looks like it would go somewhere around the drivers seat. No clue yet what that was but will do some investigating.

Tom
What colors is the cUT wire? if I recall correctly there is purple wire that goes along the inner rocker to the seat belt retractor. There is another wire that goes to the optional seat back release.

 
Finally getting back to this after a long year of focusing on other things. I took the captive bolt loose and it came completely out, wasn't captive at all. The green plug is loose in the metal bracket but refuses to come completely out of the metal bracket. The green plug has a lot of play to lift up on but I can't get it away from the bracket, what am I missing? I did notice that when I pulled up on the top of the green plug, a couple small pieces of green plastic fell out so I did not really try to pry or pull real hard. The fuse block portion came loose and hangs down after the bolt came out, is the fuse block two pieces and there is a back side of the plug still connected maybe?. Anyone have any ideas? Thanks for all assistance.

Tom

 
There are two locking tabs on the green connector block with male pins.  Simply squeeze inwards and push the connector backwards away from the metal bracket.

You are missing an "e" clip on the bolt that holds the two connectors together.

 
There is also a metal tab that is folded over and holds the harness up against the bottom of the cowl, on the drivers side tucked up in the corner above the parking brake.

 
OK, I am starting to feel like a dumbass, for some reason I still cannot get this plug separated so I can remove the harness. I see that David posted pics of the green plug separated, but I do not see the Tabs to press to separate them. Anyone got a close up pic of the tabs. Thanks and end the end, I know that it is probably going to be so simple and really make me feed stupid. I appreciate the assistance as always.

Tom

 
Have you loosened the bolt from the fuse box front yet?  Is the fuse box out of the way?  If so, you should be able to see those locking tabs.

 
Here are a couple pics of what I can see.  I do think that the tabs are missing because I can't see or feel any types of locking tabs and the plug still refuses to separate.  There is a lot of play where I can pull the plug through the metal plate and see almost the whole assembly. I have never had this much problem separating a simple plug like this. Thanks for any suggestions.

Tom

20200817_182138.jpg

20200817_183201.jpg

 
The top picture is the underdash harness side of the connector.  The locking tabs are on its mate.  I see that your bolt is removed allowing separation from the fuse box, but is that bolt broken off?  If it is, that would cause your problem, as the bolt screws into the connector in the bottom picture.  The bolt remainder would have be captured by the underdash harness connector.  That connector is already damaged as it has mounting tabs broken off that fit into the fuse box.

How did the bolt get removed?  Typically, all you need to do is to loosen the bolt (it is captured with an e-clip) and then pull the fuse box/green connector plug as a unit, leaving the headlight harness green connector locked into the bracket. 

 
Thanks Midlife, as far as the bolt coming out, I put a socket on it and it came loose right away. It was not stuck or super tight at all. I checked per one of your previous posts about the clip that holds the bolt in and like you said, it was missing. I have not checked the end of the bolt to see if it was broken, that would explain a lot. If it is broken, I guess I will have to wait to remove it until I remove the dash later this summer.  Thanks, I appreciate the assistance.

Tom

 
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