toro455

I'm trying to re-install my tach / clock after having the clock repaired and am having trouble remembering where the wiring goes. I've got a manual and it shows where the shielded wire ( braided ) goes on the back of the tach. The shielded wire has a inline fuse ( 2A I think ) and a round connection that goes on the stud ( drivers side of tach in installation position ).

The orange wire is for the clock which is attached to the passenger side of tach on a male connector.

What I have left is a black wire with round connector that drops down from the upper wiring harness. Has a round connector with "teeth" on the inside. Does that wire connect to the tach, and if so where. If it doesn't is it just a ground that needs to be connected to the inside of the dash ?

I know I should have labeled before taking this out but I thought it would be simple. I can't find anything in the manual that shows exactly where this mystery wire goes and can't find anything additional in the forum.

If someone has some photos of the wires still attached to the back of the tach on a 1970 442 I could really use it for reference.

Thanks so much, I'm trying to put my car back together !

w-30dreamin

Does this help?

DSC03715.jpg

rcorrigan5

W-30dreamin's wires are hooked up just like the ones in my '69, except that I don't have a braided wire associated anywhere with the clock/tach. The grey wire is for the dash lighting and plugs into the dash lighting harness. The brown wire with the in-line fuse is for the tach (it goes to the negative side of the coil) and the orange wire slips on the blade connector for the clock.

Is the braided wire a ground? I have a short black wire that runs between the speedo pod and the clock/tach pod that serves as the ground (held on by the small screws that attach the pod to the dash).

Randy C.

toro455

Thank you both for trying to understand what I was saying. W-30dreamin's photo shows what I had a hard time explaining. I think that the only remaining unanswered question is the short black wire with the round connector ( with teeth ) that is part of the upper wiring harness. It goes above the gauges in the instrument panel and hangs down about 3" right above where the tach opening is in the gauge cluster. I'm going to try and photograph this so that I get the attachments right the first time.

Randy C., I think you understand which wire I'm talking about but I will take a photo and try to post just to be sure. Please let me know when you have a chance. I will also post the braided wire I was talking about.

Thanks again for your assistance !

toro455

Here are some photos of what I was trying to explain earlier. I also found a yellow wire with no connector on the end ( any ideas ). I originally thought that the orange wire with the female connector went to the tachometer but now I think it might be for the glove box light.

Do the connections look right so far on the Tachometer. I did this based on what the manual showed.

The black wire is shown in some of the photos with the round connector and the "teeth". I was wrong when I first described it. It actually comes out of the lower wiring harness but still is aligned with the tachometer opening.

When I got the car the clock was busted and hadn't been working for an unknown period of time. Could the mysterious yellow wire be missing the "female" plug to be attached to the right side of the tach ? Which would look just like the orange wire with the female connector pictured which I now think should be attached to the glove box light.

Anybody know where the black wire goes ?

toro455

More photos...

toro455

Here are some photos that can be enlarged...

extreme1

black wire looks to be a ground wire. whether is grounds to chassis, or the guages themselves I am not sure.

w-30dreamin

I'm sorry I don't know about the black or the yellow wire.

The shielded wire hooks to the metal ground tabs on the dash housing for the instruments.I think your shielded wire is in the wrong spot.

extreme1

yes if you leave the braided ground strap where it is, I'm pretty sure your car won't run.

rcorrigan5

Is there a screw, or screws, that hold your tach pod from the back side into the dash? If so, I'm pretty certain that is where your black wire should go as well. The black wire will provide the ground for that pod. The braided "wire" throws me - it's not present on either my '69 or '68 4-4-2 cars. Does the braided "wire" go around the brown wire after the in-line fuse? If so, I see the braided "wire" as a ground as well and I would tie it in with the black wire to the tach pod where the screw(s) attach the pod to dash from the back side. Having the braided "wire" where it is now does nothing. Keep in mind - I'm not an electrical expert and what I'm proposing here is just an educated guess, in particular with the braided "wire".

Randy C.

toro455

Thank you all for your input...I agree that the black wire with the round connector is a ground, I just need to know where it goes.

The yellow wire is still a mystery but may have something to do with the clock I think as the orange wire with the "Female" connector ( in pictures ) belongs to the glove box light.

Now you are saying that the braided wire is a ground. I checked the manual again and found a diagram (12AA-3) that shows a ground wire attached to the front of the tach when installing in the instrument cluster. That same wire is attached to the back of the tach also according to the diagram. I just can't tell which wire it is. Maybe the braided wire ?

The braided wire also contains the brown wire with the inline fuse. I figured all these wires would be common to anyone with a tach / clock combo. Especially this braided wire.

w-30dreamin

On the back of my tach there is a male spade terminal,this is where my orange wire hooked up.
The brown wire that has the inline fuse and is hooked to the stud with the nut hooks to the - side of the coil.
The braided ground wire attaches to the dash grounding metal where the attaching bolts hold the tach in.That sounds like what you are describing about the ground going to the front of the tach.



I just reread your original post and realized your working on a 70,mine is a 71,don't know if there is a difference.

rcorrigan5

I concur with W-30dreamin. I'd go further to say that the black wire also is tied in with the braided wire. Also, see in the Electical Forum, under the fairly current entry "Rally Pack and Electrical" by "Borry" (about the third entry down from the top), the answer by Joe Padavano. He explains what the wires do as well.

Randy C.

toro455

I did check the other threads regarding the "Rally Pack and Electrical" as Randy C. suggested. I think the black wire with the round connector is a simple ground from the lower wiring harness. I will attach to the back of the instrument panel not to any of the gauges.

I have searched this forum using every combination of words I can think of and I still cannot find anyone who can tell me what the shielded ( braided ) wire with the round connector gets attached to exactly.

I think I understand where the other wires go so I'm doing OK there. It sure would be nice to have a photo of the exact location the shielded wire is attached. I sure wish I would have taken a photo before taking it apart.

Can anyone help with the shielded wire location ? Again this is for a 1970 442 with original wiring.

Julian P

Hey guys.. the assembly manual shows you exactly where each wire goes...can get thoses at year one, fusicks...will check mine when I get home...

years ago I put a factory rally pack in my 71 and only had to change one wire and it has worked near perfect ever since...

BlackGold

The braid is a shield surrounding the brown wire from the negative post of the coil. It reduces the RFI which eminates from this wire and would otherwise possibly interfered with the radio.

The reason you don't see the braid on the tach wire on 1968 and 1969 cars is because the braid was not added until part way through the 1970 model year. It was pretty early in the year (late 1969 actually, if I remember correctly), but there were some 1970 model cars built without the braid. Mine's one of them.

You can investigate such matters by learning to decode the revision history chart at the bottom of each page of the assembly manual.

toro455

Julian, I did check the assembly manual and it doesn't show where the shielded wire round connector goes. Maybe the page in the assembly manual I have is missing but I checked there and in the service manual.

I think what it's going to take is for someone that has a similar car to check where the shielded wire is installed on their car. Thank you for taking the trouble to look at your car. Maybe someone has some photos of the right location where this wire is installed....

toro455

Well, I checked every page in the assembly manual ( 1970 442 ) and found the diagram for the shielded wire. My manual is so faded it is hard to see the actual location. I determined it was connected to the upper center attaching screw for the heater control assembly. That is what the manual shows for those that wondered. I figured out that the yellow wire I had under the dash that did not have a connector was power for the radio which hasn't been working in who knows how long.

I got a FM conversion done on my AM radio with the MP3 player plug. All the internals are new and I can't wait to put power to this. I bought the dash speaker with the two speakers and factory look and two 6" x 9" speakers for the rear which are not visible on the package tray. Very nice stuff !

Boiler_81

Reviving and old thread.

I am detailing my engine compartment while the engine is out being rebuilt. I removed the harness and found no braided wire. The car is the last week of 69 production.

What was strange is the tachometer wire (which is part of the instrument panel harness) is run through a grommet on the firewall and is then taped into the engine harness. The engine harness could not be removed without removing the covering tape in order to remove the tachometer wire.

I have a new engine harness on order. I am going to have to tape in the tachometer wire for a factory appearance.

344670

Morning, where does the other side of the braided wire connect to inside the engine compartment? 1970 442

rcorrigan5

That should be the "brown" wire that has the in-line fuse. It goes to the negative side of the coil.

Randy C.

344670

Yes thanks. That's great. The shield starts 6-8 inches away from the negative terminal.

oldcutlass

It does not connect to anything, its a floating ground, thats only connected on one side.

344670

I sure could use some help. I plugged the brown wire on the negative side of the coil and you guess it.... the car won't start. Unplugged it, starts fine. Obviously the sheild caused the coil to be grounded How should I proceed here? Run a totally new wire without sheild or just disconnect the sheild from the back if the tach? Second question. Does this mean the sheild is rubbing on the bulkhead?

oldcutlass

Where is the shield connected? It should be connected to a ground not the same place as the brown wire on the back of the tach. If its connented to ground then it may have chafed through the insulation of the brown wire creating a short.

344670

The sheild is connected to that little screw towards the bottom right hand side of the tach. In other words, it's On the tachs back shell.

344670

I just ohmmetered the brown wire to ground. It's open. But thé sheild, instant ground. If I disconnect the shield under the dash, would I be ok?

oldcutlass

Disconnect the shield and let it float so its not touching anything and connect the brown wire to the negative side of the coil.