Wiring tach

[claf]

I am trying to reassemble my Tiger dashboard (which I did not disassemble) and am stumped on the tach connections. Per the wiring diagram it looks like the green (power) wire connects to one of the terminals and the white wire (signal) just connects to the other and then keeps going. So far so good. On the back of the tach there are two connection points, one blade connection and one small round connection with a knurled nut on it. Which is which ? I suppose I could figure it out by trial and error but don’t want to take a chance and goof up. Thanks, Bob

[Joel & Karen Griffin]

The white signal wire loops thru a small plastic block an go’s on the post with the knurled knob.

[Eric and Bonnie and Bonnie Gibeaut]

Also make sure that there is a U shaped metal clip that fits over the plastic block and white wire assembly and the whole assembly fastens to the post with knurled metal knob. This assembly is the inductive pickup that makes the tach read the correct RPM. Eric

[claf]

Ok guys, now that I’ve actuallly looked at the tach, I understand where and how it connects— which brings us to the second part of the confusion. Where that tach wire comes out of the harness there is about 8 inches before the little plastic gizmo and then about another 24 inches after the plastic block Does this end connect to the ignition switch ? If so, where in gods creation is the other end ? I’ve got a pretty good idea where it ends up (ballast resistor ?) but I have no idea where it exits the harness. I’ve been running a continuity light for a couple days now and can’t find the engine side end .

You have to forgive me for asking simple questions but this car had a "custom dash" and the PO used mostly orange or brown wire for EVERYTHING. Most every wire under the dash has been spliced and naturally has lost the correct color code. Kind of a fun part of the job but frustrating at times. Typical example, all the gauges were aftermarket so he tossed the voltage stabilizer and paired up and dead-ended all those wire. Bob

[mainetiger]

CAT sells a wiring diagram of the dashboard which would probably be very helpful for what you are doing. It shows all the connections as well as the wire colors.

Tod Brown
B382002384LRXFE

[tiger-tr6]

Speaking of tack wiring . . . . . I am reassembling a Mk1 (which I didn’t tear down). The dash was out of the car and since the old wiring harness had gone through many mods I am using an new harness. For the tach wiring the old harness retained the plastic "wire loop" holder, but no sign of the "metal clip" mentioned in this thread. What does the clip look like, and can I just fabricate a replacement from some ferrous metal, or is it something "special?" The car is an interesting project. I had a Mk1A "wayback" but never delved into the underdash wiring.

Thanks
Bob in York

[Gene & Anthony Padgett]

The little clip for the inductive tach connection is indeed ferrous. I thought it was copper. but my magnet says otherwise. Must be anodized, or maybe copper plated. It looks pretty easy to replicate.
It is basically "U" shaped with squared corners.
Both arms and the center section are very close to 1/2 inch long. The two arms have rounded tips.
The middle piece has a hole drilled offset from the center, about 6/32 from one of the side legs, to allow the clip to slide onto the threaded post of the tach connection and position the legs over the two metal tabs rising out of the tach connection.
The rounded tips of the arms slide down into the slots next to the two metal tabs with round tips rising up out of the tach connection and make contact with them.
The arms are about 6/32 wide and the center section is wider at about 10/32, probably just to make a firm seat for the knurled nut and toothed washer.
There also is a small hole in the center section roughly at a mirror image location of the hole for the threaded post. Smaller than that hole but I do not know if it serves any purpose.
Material thickness looks to be 1/32.

Hope that helps.

Gene

[tiger-tr6]

Gene – Thanks for the detailed description of the metal clip. I will check the "parts boxes" again since I have an idea of what I’m looking for. However, my bet is that it was lost somewhere in the "transitions stages" for the car. I can probably fab a replacement unless the inductive qualities of the original clip are somewhat odd.

Bob in York

[Gene & Anthony Padgett]

You’re welcome. I just happened to be up late and a tach and stainless steel ruler was within reach so I said why not!

Gene

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