Is my tach original?

[cobra460jet 10]

Can anyone tell me if my tach is original. My 69 Mach 1 390 automatic car has a tach in it but I cant tell if it came with it. I also cant find the build sheet. I heard the headlight harness and altenator harness are different. Does anyone have a picture? Tach doesnt currently work and someone did some wire hacking on the back of the insrument cluster...

[jmlay 80]

Difficult to tell without a visual. If it is not original the wire harness would have been changed or hacked up like this to install.:

 

http://www.boss302.com/tach.htm

[69gmachine 15]

With a 40 year old car, the only way to know for sure is to get a Marti report. My car didn't originally come with a tach, but I've installed the factory underdash tach harness, engine bay harness, and alternator harness, so it all looks and functions as if it came that way.

 

From the sounds of it though, it would appear it was added and the non tach underdash harness was modified, but not good enough to make it actually work. The other wires going into the back of the instrument panel aren't in the same places on the connector either, so unless they were re-pinned, there will be other dash lights and gauges that don't work.

[cobra460jet 10]

I got my buddies wiring harness from his 69 windsor car. His connector that goes to the instrument cluster has 13 pins. his is a non tach car. My connector has 14 pins with totaly different wires and colors. I know this could mean nothing but I got two resistance wires which he doesnt. I was told too look for a green connector on the headlight harness up in the front.

[miketyler 15]

And then his 40 year old tach may not be working. Am curious if there is a way to bench test the tach off the car?

[buening 63]

I believe you can test it for continuity. The tach is wired in series with the coil, so when the tach fries the car won't start.

[danno 128]

If I remember right, the tach uses it's own connection on the back of the inst cluster. All the other pins on the cluster interconnect are to change connections from gauges to idiot lights. If your tach is not working, it is either not connected, bypassed, or broke. Do you have the 2 wire connector on the back of the tach? It should connect to the underdash harness that goes to the engine harness. The engine harness is not the same as the underhood (or headlight) harness.

[69gmachine 15]

If you have the correct underdash harness, then the tach was probably bypassed in order for the coil to fire, which would leave me to believe the tach was bad (open). The tach should have red and black leads coming out of it that plug into the underdash harness as danno described.

[cobra460jet 10]

If you have the correct underdash harness, then the tach was probably bypassed in order for the coil to fire, which would leave me to believe the tach was bad (open). The tach should have red and black leads coming out of it that plug into the underdash harness as danno described.

I believe your right. There was a wired installed/run to the coil that someone done. The wires red/black coming off the tach were spliced into some other wires. I undone the mess that someone done and now Im trying to straighten it all back out. Problem is I wish I knew if this tach was original. I keep looking at pix on e-bay trying to identify a tach harness headlight/underdash/altenator. I cant find the build sheet. Im going to get a marti report and also called DMV to have a title search done on it. Supposedly there has only been three owners of the car. None of my wiring diagrams or the wiring assembly diagrams even show a tach harness... gggeeessshhh...

[buening 63]

Basically, if you pull the instrument cluster out away from the lower dash you will see the dash harness running across the top of the lower metal dash. To the right of the steering column there would be a pigtail coming out from the taped up dash harness with the black and red wires with the two pin connector. Pretty much, just follow the harness from above the steering column to the right above the radio and see if you can find this pigtail. If you don't find one, then you don't have the tach dash harness. With that said, you don't need a tach harness if you install a factory tachometer. The link jmlay posted has instructions on the wiring modifications needed to do this without swapping harnesses. I have done this personally it works great.

[danno 128]

You will need to figure out if your tach works, though. If you have an ohmmeter, put it on the leads to the tach. It should read a low resistance. If it reads anything over 100 ohms, the odds are your tach is burnt "open".

[cobra460jet 10]

Ok guys got my Marti report today. It says nothing about having a factory instaled tach in my automatic car. Also the original altenator wiring harness is for a non tach car. It has 3 wires on the plug instead of 4 like the tach cars. Im still trying to find out if the headlight harness is a non tach harness. But its really dificult to tell. Anything to look for on it?

[prayers1 153]

If your still having problems. Get in touch with Randy at

midlife66.com/wiring/wiring.html

[jmlay 80]

What is the part number on the harness, should be a wrap around the harness somewhere. But is sounds like it has been modified too add the tach, see the instructions in my precious post to help identify the modification.

[1969 Mach1 14]

Can anyone tell me if my tach is original. My 69 Mach 1 390 automatic car has a tach in it but I cant tell if it came with it. I also cant find the build sheet. I heard the headlight harness and altenator harness are different. Does anyone have a picture? Tach doesnt currently work and someone did some wire hacking on the back of the insrument cluster...

 

Do you have a wiring diagram? If not, get a copy and just compare it to the wiring at the IP connector. I have modified a non tach harness to work with a factory tach including the changes needed to correctly switch from an ammeter to an alt warning light. Which by the way requires the majority of the changes. The wiring and color codes are different at the IP connector for tach vs. non tach cars. Also, back in the day, most if not all automatic transmission cars did not come with tachometers.

 

Compared to toays tachometers, the factory tachs don't work very well anyway. And if yours still works it probably won't for much longer. Since the movement and isolation transformer typically fail and are no longer available, you have to decide to either have it repaired with used parts or retrofit with internals from a 2-1/16" dia. VDO tach.

 

Having sold a 1970 Mach 1 complete factory tach cluster recently their value today is half of what is was about 5 years ago. Also, individual gauges for a tach cluster are not reproduced and near impossible to find. People just won't part out these clusters. If your tach cluster ends up not being original to your car and is in need of restoration you might want to consider reinstalling the non tach cluster.

 

In conclusion, don't get too exited over a factory tach cluster.

Edited November 7, 2011 by 1969 Mach1

[cobra460jet 10]

What is the part number on the harness, should be a wrap around the harness somewhere. But is sounds like it has been modified too add the tach, see the instructions in my precious post to help identify the modification.

The tag on the under dash harness is a light purple in color. Has the following written on it... S/X-F C9ZB 14401-AE. On the lower portion of the tag it looks as if it reads 14401 - AF... I contacted DMV in NC today to do a title search on the car. Hope to get in touch with the previous owners to possibly find some of the original parts and history on it. If I knew how to post pictures I would. I dont know if all this Tach stuff is really worth all the headache. I think Im with 1969 Mach 1 on his quote.. "Dont get to excited over a Tach".

Edited November 8, 2011 by cobra460jet

[LiLMike 42]

I know I was going nuts trying to figure out what to do about gauges and a tach. Check out this thread.

 

http://1969stang.com/mustang/forum/showthread.php?t=10617

[1969 Mach1 14]

I didn't want to sound negative with my statement, "don't get too exited over a factory tach cluster". I use to think it was one of the greatest options offered in these cars.

 

But it really became a headache when my factory tach started to intermittantly work, then stick at times, and eventually stop working completely. And for some reason when it did work I went through four or five MSD Tach Adapters at $50 each (yes, connected for a current triggered tach). I researched repairing or retrofitting it and discovered first hand that the 1969-1970 tachs often cannot be repaired because the movement or isolation transformer that commonly fail are no longer available new. This only leaves retrofitting as a means of getting some of these factory tachs operating again. Which does in fact work but didn't appeal to me because these have to retrofit with the tiny components inside a 2-1/16" dia. VDO gauge.

 

The only other drawback to these factory tach clusters is the lack of oil pressure and ammeter or voltmeter gauge. You can add two aftermarket gauges with the available "Shelby Mimic" gauge pod down at the console ashtray. That works and looks great, however, for me I found those gauges so far out of my field of vision when driving I never looked at them.

 

Since this factory cluster wasn't original to my car I choose to remove the underdash and engine compartment wire harnesses, undo all the wiring changes I made, and reinstall the original non tach cluster. I then added an Autometer 3-3/8" dia. tach. I was able to clamp it to the steering column and position it so I still see all the gauges as well as the tach. I was shocked how much better this Autometer tach works than the original factory tach ever did.

Edited November 8, 2011 by 1969 Mach1

[69supercj 0]

I know I’m resurrecting a very old thread but I have the same under dash harness that you have, C9ZB-14401-AE and I’m trying to find out what this fits. What options do you have on your car? This might help me narrow it down.

[danno 128]

The tach cars had a underhood and underdash wire harness unique for the use of the tach.  If the connector to the alternator has 4 pins to connect it to the underhood harness, the odds are it is a harness made for a car with a tach.  It it has 3 connectors, then it is definiately not a tach harness. 

For the underdash harness, there are clues that can be made if you have access to the connector that connects to the  back side of the instrument panel.  They colors of the wires and where they connect are different between a tach and non tach car.   

Someone else might be able to tell you what the part number is on them.  I do not know.  Maybe look at CJ pony parts for the part number and see what it cross references to? 

[Midlife 814]

Master Parts Catalog cross-references the C9ZB-14401-AE  to C9ZZ14401-A, which fits a Mustang, no AC or tach, and not for a Boss 302. 

 

[69supercj 0]

35 minutes ago, Midlife said:

Master Parts Catalog cross-references the C9ZB-14401-AE  to C9ZZ14401-A, which fits a Mustang, no AC or tach, and not for a Boss 302. 

 

Thanks Midlife! So will this underdash Harness work in a Mach 1 or a deluxe interior car, you just plug-in the harnesses for the deluxe door lights deluxe clock Consol etc. into this existing harness? 

[Midlife 814]

Yes, this is the standard underdash harness without AC and without tach.  I'd guess 50% of 69 Mustangs used it.