I searched through several older threads on Dixco tach, looking for a schematic for the internal wiring, and discovered many guess's and incorrect methods for wiring these tach's. So here it is. 60's (at least) Dixco tach's have three wires. I have three a model 97, a 3-5665 (which was made for NAPA) and a late 60's which at this moment I do not have the number handy. All three have three wires. Black, White, Green. Correctly wired Green - Sender to - (neg) side of coil, or tach terminal on a HEI dist. White - Ground Black - + to either + side of coil, or ignition terminal from Ign switch. No one seams to understand the lack of a red wire, and most want to use white for red. Modern tachs use 4 wires, one red. Actually it is perfectly logical if you are used to working on the electrics of older cars. In the 50's and 60's I know for sure, Black was mostly used as a Hot Color. I recently studied 50's and 60's Ford and Chevy wiring diagrams and very little (if any) red wires were used. Also Green was rarely a ground. Black was mostly if not always a hot color. Another tidbit if the bulb is bad on one of these 3 wire tachs, it either will not work or read incorrectly. If you unhook the ground it will work, (may not read correctly). My guess is it picks up a ground from bad bulb or may be a back feed. With ground hooked up won't work at all or reads really low. I discovered this today on that NAPA blue line tach. Someone tore it apart and pulled wires loose from board. I finally found a fuzzy picture here and was able to rewire it. So since in my searches I found more questions than answers on the correct hook up of these tach's I thought I'd pass it along. Also None of the Dixco tachs I have ever found require a sending unit. If they don't work when hooked up this way, some componet is bad. Just remember if no light operates, put a bulb in before you tear it apart, or condemn it to the neat, (but non functional) parts shelf. Hope this helps someone out.
Your wiring chart contradicts everything I have ever read on Dixco wiring. Green -side of the coil White light bulb Black ground Do you have your Dixco 3 wire hooked up the way you show, and it works?
I hooked up a Dixco model 97 Tach in my truck tonight following this dlotraf's process. Green - Sender to - side of coil White - Ground Black - to the + side of coil, What I though was a bad tach is now working well. Really appreciate this thread. Thanks!!!
dlotraf, your instructions helped me as well. Installed a HOUSER brand, much like the Dixco, in a 62 Falcon 6 cyl. Exactly as you explained. Thanks.
I have a Dixco 97. I have three wires, Green, black, and white. The white wire is not attached to anything in or on the tach. Where does the white wire get attached to on the tach? Any and all help would be appreciated. Thank you.
Could you take the cover off and take a pic? I recently posted on a NAPA tach which may be made by Dixco. If so, when you get the back off, on the NAPA, 2 of the wires went directly to the light bulb socket. The -coil wire was soldered to the circuit board.
For the record... I just hooked up my 6v Dixco tach in my '51 3100 as dlotraf instructed... Green - Sender to - negative side of coil / White - to ground / Black - to switched positive (at ignition switch) ...and it works perfectly. I originally had the black and white reversed and while the bulb lit up the needle did not respond.
After reading this thread, I thought this schematic might solve your questions for hookup. These diagrams come from the box to a Dixco model 97.
The green wire is soldered to the circuit board, the other two wires go deeper into the tach. I am not going any deeper into it, as things tend to fall apart on me. Hope this helps.
Thanks all-I hooked mine up as per Dixco's instructions from !ac's post, and it worked. Reversed the black and white wires, nothing happened.
Thanks alot, im going to hook up my old Dixco 97 tach when I get home from work. It was a $10.00 swapmeet find, I hope it works. Posted using the Full Custom H.A.M.B. App!
I just picked up a Dixco model 793, looks just like a Sun Super Tach.. I haven't hooked it up yet but wanted to check everything over before I install it in the car. How do I get to the light bulb to replace it? I got as far as taking the back cover off. I see two empty holes that look like a light socket would fit, but no socket or wires that show one was there... im kinda afraid to dig deeper.
Hooked it up and it seems to work good. Gonna throw my timing light tach on there tonight to check its accuracy. I don't see the light on, but its pretty bright out today so I'll check again after it gets dark. If nothin else it sure does look right!!
Hi guys I'm buy a 97 Dixco tachometer for my 6 v 6 cyl and positiv ground, Small question What is that I have to remove resistor or not,I'm not sure Thanks
It's just not late model tachs that use four wires. I'm a big user of vintage Sun Super Tach ll's (no box required) all use four wires.Black- ground, Green- trigger, Red- 12v power, white - light. Gary
Old thread but I remember years ago the guys who connected the positive wire to the positive on the coil had trouble. Problem was it's not 12+ volts and was the resister volts.
Hmm. Reading this reminded me I have an old Dixco tach I found in a truck I bought. Just dug it out, don't see a model number but it's small, 2 1/4 face and a bullet shaped housing. 2 wires, green and tan. Any ideas? I suppose the tan might of been white but aged but the tan is an even color all over. When I get a chance guess I'll pull it apart and look to see if I'm missing a black.
Had that same tach back in the 60's and early 70's and probably have it in the file cabinet in the shed. I am thinking it had 4 wires. Hot, ground coil and light. Had it in my 69 Cutlass and then in my 48 for a long time.
OK, took mine apart. It's a model 47. Green wire goes to the circuit panel, tan (and it is definitely tan) is soldered to the light bulb base. Missing wire I assume was black soldered to the light bulb pin. I'm assuming other then using the tan in place of the white I just got to add the missing black and try it out. I can't believe there is not a socket for the bulb, it's just stuck into a hole on the board and wires soldered direct to it. Also I find interesting the bulb is green.
Btt!!! In my 6V 6 CYLINDERS Ford & positive ground I'm I connected as indicated on the plan, but it does not work, I connected well the black on the ground, the green on primary distributor and the white? Am I obliged to connect him on ignition switch Or what is that I can connect it somewhere else? Thanks for your help
It's OK , I'm connected the black to the ground & green on primary distributor and it's work good !!!no neccessary to connect the white !!!
I know this is an old thread, but I found it with a search. I have this identical Dixco 47 tachometer. It was inoperative...the bulb was bad and the OP said they can be inop with bad bulb. So I replaced the bulb and now it’s inaccurate. The difference between the one in the photo and mine is, mine doesn’t have the thermistor I’ve identified in the photo. Might the issue be because of the dual point layout of the distributor? Any experts out there that can tell me that is my issue and need to install one? Any input would be greatly appreciated fellas! It’s in my coupe with a 59A-B with a stock distributor.....thank you!!
Are you sure that is a thermistor. Capacitors also come in that disk configuration. I suspect that there is a capacitor on your circuit board - it just has a different form factor (the meter movement tracking RPM requires a resistor-capacitor circuit). The fact that it now works makes me believe that it is now a calibration issue. Back in the day, many tachometers came ready for 4, 6 and 8 cylinders. The instructions had you cut out resistors or jumper wires for the cylinder count of your engine. Also, is the replacement light bulb the same part number as the bulb that you removed. A brighter or dimmer light bulb will have a different hot resistance. Define inaccurate - Post #17 shows a resistor across the meter terminals (inside the cup). You "might" be able to calibrate the tach by varying the resistance across these meter terminals. Also look for signs of cut jumper wires Russ
Thanks for the input Russ. I’m taking it apart again when I get home from work and I’ll give it a closer inspection and see if there’s any witness marks of a jumper or other solder points... I’ll get some pics too and post back....thank you!!
My 56 Bird has a Dixco, still in the car- hopefully there is a wire from the tach with the coil wire. Now I have to go look lol
When I first opened this thread I thought I would look at my Dixco tach that has been on my car since I bought the tach years ago and post the findings but after reading on it looks like several others have.
Reviving this post. I have read through about every thread I could find with no results. Dixco tach that I just bought off ebay. (Is still in shipping at the moment). I guess it may have been rewired at some point, but it has a black wire, a white wire and a red wire. No green. FWIW, seller claimed it "worked when removed". I'll attach pics. Hopefully, if nothing else, one of you guys can tell from where each wire is attached inside, what to hook it to, despite the wire colors. Any input appreciated.
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