78-79 Magnum guages.

[dodge1972]

Plan to install a set of gauges with a tachometer in a non-tachometer dash. Other gauges are also configured differ. My concern is the dash wiring harness. Are the wiring harnesses the same for Magnum with or without the tachometer? I expect to add wiring to the ignition system but I need to consult the wiring diagram to access the Tachometer. Thus the question will the replacement gauges work with the original harness?

 

[Pete Kaczmarski]

To the best of my memory the wiring harness was the same but it was relatively easy to change to give it a try.

 

[soupguy]

I just checked my 79 service manual, the harness will be missing the wire for the tach pulse which is position 1 on the cluster connector, its probably the case in 78 too. I do not believe this wire went through the bulk head connector, looks to go though the fire wall some other way to the coil so I wouldn't think it would be hard to add

 

[dodge1972]

I just checked my 79 service manual, the harness will be missing the wire for the tach pulse which is position 1 on the cluster connector, its probably the case in 78 too. I do not believe this wire went through the bulk head connector, looks to go though the fire wall some other way to the coil so I wouldn't think it would be hard to add

Checked the backside circuit strips. Appears you are correct. 12 pin connector should read as follows:
Pin 1 Tech, Pin 2 Temp gauge pin 3 indicator Lamp pins 4 & 5 are the alternator current, Pin 6 indicator lamp, pin 7 fuel, pin 8 oil, pin 9 indicator lamp, pin 10 indicator lamp pin 11 indicator lamp and pin 12 indicator lamp. Please check if this is correct. I can cross check with the original dash pins. Assume the back board land for interconnect is differ for the non-tech version. Thanks

 

[Micah Pohlman]

Plan to install a set of gauges with a tachometer in a non-tachometer dash. Other gauges are also configured differ. My concern is the dash wiring harness. Are the wiring harnesses the same for Magnum with or without the tachometer? I expect to add wiring to the ignition system but I need to consult the wiring diagram to access the Tachometer. Thus the question will the replacement gauges work with the original harness?

The cluster harness is the same but is missing the one wire of the tach signal coming through the bulkhead and the power/ground will need to be added (they might be the same wires for the clock set-up). The printed circuit board is the same for clock and tach clusters. It's a really easy upgrade, basically all you need is a tach head, I've done it many times.

 

[dodge1972]

The cluster harness is the same but is missing the one wire of the tach signal coming through the bulkhead and the power/ground will need to be added (they might be the same wires for the clock set-up). The printed circuit board is the same for clock and tach clusters. It's a really easy upgrade, basically all you need is a tach head, I've done it many times.

Appreciate your taking the time to respond.

 

[soupguy]

Grabbed these from my 79 service manual hope they help

 

[dodge1972]

Grabbed these from my 79 service manual hope they help

View attachment 962208 View attachment 962209 View attachment 962210

One set of manuals I need to purchase is the late model b-body books. Again I apricate your taking time to respond to my inquire. Your information confirms the installation. Planning to have my dash recovered, this will provide an opportunity to replace the gauges. I also have an extra set of gauges in storage. I need to check which set I plan to install.

 

[d9103365]

Following this thread with great interest as I'm trying to do the same thing on my 75 fury sport. I would love to hear any updates! for those interested, the circuit board is indeed different on my car between tach and non-tach dashes. I've also purchased the additional gauges needed, the fascia from a tach car (because the gauge names are different) and also a harness which is available as a reproduction.

 

[rumblefish360]

I did the swap. Plug and play deal.
(FWIW, looking for a tachometer, speedometer cable)

 

[d9103365]

I did the swap. Plug and play deal.
(FWIW, looking for a tachometer, speedometer cable)

Did it really plug right up to the harness? What about the line for the tach pulse that the previous posters mentioned....did you not have to run a new line thru the bulkhead for that?

 

[d9103365]

BTW, currently my dash only has the "idiot light" for an oil gauge, but with the new tach setup, I'll have to use the REAL gauge, which I purchased....will it hook right up and work properly without anything additional?

 

[Micah Pohlman]

BTW, currently my dash only has the "idiot light" for an oil gauge, but with the new tach setup, I'll have to use the REAL gauge, which I purchased....will it hook right up and work properly without anything additional?

The extra feed for the tach can be routed though any hole in the fire wall or (what I would suggest) go through the bulk head connector. You'll need a electrical FSM, find the right cavity add a wire to the dash side using the right connector and run that up to the cluster. Adding the engine side wire is easier because you won't have to stand on your head to see what you're doing. If you have idiot lights you'll need to change the oil pressure sending unit to match the gauge.

 

[dodge1972]

If anyone is interested, I have a set of gauges from a 78 magnum with a tach unit for sale. send PM if interested

 

[rumblefish360]

If anyone is interested, I have a set of gauges from a 78 magnum with a tach unit for sale. send PM if interested

(FWIW, looking for a tachometer, speedometer & cable)

 

[DodgeBoy5150]

Grabbed these from my 79 service manual hope they help

View attachment 962208 View attachment 962209 View attachment 962210

My 1977 service manual shows the same--so bummed--just got a tach and gauges for my Cordoba--unfortunately no PCB.

Eventually I will get around to pulling out the instrument cluster and find out for myself--when I do I'll be sure to post pics ;-)

 

[DodgeBoy5150]

So I started messing around with my factory tach today--wanted to trial fit it. I got a complete Cordoba cluster for cheap--thought I could get everything fitting on the bench before trying to disassemble my original in my car. Damn--looking like a PITA!

1. The tach won't fit without drilling a hole--no prob--hole saw was a little too big ,but, worked.

2. Tach fits perfectly--or so it seems.

Looking good at this point so I install the factory tach PCB that I scored--and that's where the install grinds to a halt.
PCB fits perfectly ,but, there is no way the tach will now fit.

So either I have the wrong tach to fit this model year ('77) or the wrong PCB--either way I know I can modify the current PCB ,but, what a PITA!!