center gauge hook ups

[mikepasquale1]

My car did not come with the center gauges. I do have the gauges in the car though. Anyone have any ideas on how i can hook them up. I know i wont get the ammeter, im not worried about that. Id like to get oil and water working. Also is it true that the gauges only use 5 volts to work. If so how can i accomplish this? Im capable of building a harness but i dont want to fry the gauges

 

[Steve73QMach1]

Mike - it has been 32 years since I performed this addition on my Mach 1. I did get them working though. The first thing you need to do is to change the switches used for temp and oil pressure to sending units that are used with gauges. These are readily available. The oil press switch on the 351C requires a special socket to remove it (you may be able to get it off with a regular socket but I bought the socket for $8). It is located behind the carb toward the firewall. The Temp switch is on the front of the engine. Once you have the sending units installed, re-connect the same wires that were used with the switches. The wires that go to the warning lights in the main cluster can be rerouted to the mini cluster (oil pressure wire is white with red stripe, temp wire is red with white stripe). You are correct, the gauges will require a connection to the 5 volt constant voltage unit (CVU). The good news is that your Mustang already has a CVU located on the printed circuit behind the main gauge cluster (speedometer/fuel gauge) that is used for the fuel gauge. I tapped off of the CVU line running to the the fuel gauge (black wire with green hash lines) and ran that to my oil pressure and temp gauges. You will also need to tap off of one of the cluster illumination wires (light blue with red stripe) to allow your new gauge lights to work. It helps if you have the connector/wire harness that came with the center gauge mini-cluster - it makes for a neater job even though no one will see it.

 

[JimNiki]

do non center gauge models use the full loom? If not, no probs, let me know and I'll explain. It's not that difficult. On the weekend I installed a holley electronic fuel pressure gauge which installs beautifully in place of the ammeter. It is holley 26-503. And it looks factory too!

 

[OLE PONY]

Great memory Steve for something you did 32 years ago. Sounds like good advice!

 

[mikepasquale1]

Steve. Thanks for the walkthrough. i currently do ha e brand new sending units on my motor that i got from summit. Im curioys though, whats the differences between the switches that you replaced compared to the new ones?

Whats the reason for swapping them out?

Your answer may answer my question as to why my water light is constantly on. immediately after a cold start the water light will stay on

 

[Steve73QMach1]

Mike,

The water temperature switch and the oil pressure switch are used for cars that have warning lights. They are simple switches (either on or off - no in between). If the engine temp goes beyond the preset value of the switch, the temp switch closes allowing the temp light in the instrument cluster to illuminate. The oil pressure switch operates in a similar manner. For the cars the came with gauges, sending units (not switches) were used. The sending units offer variable resistance based on the engine temp or oil pressure. The variable resistance is what allows the gauges to move in proportion to the temp or pressure. In your case, the temp sending unit offers a variable resistance (as opposed to an open circuit that you would get with the switch) that completes the circuit with the warning light allowing the light to come on.

Great memory Steve for something you did 32 years ago. Sounds like good advice!

Thanks Mike - I still have my hand made schematic from when I did that job back in 1980!

 

[midlife]

The center console connects via a small harness that connects to a unique connector that is only available on tach-dash configured Mustangs. If you have a tach dash, you only need that small harness, which I can reproduce for a nominal fee. If you don't have a tach dash, the guidance given above is correct. I can also make you a mate for the inter-connect harness connector with a wire pigtail to mate with the lines talked about above; this will help you disconnect things should you need to in the future.

 

[mikepasquale1]

I believe i bought "sending units". The my wiring hooked to them now thats probably why i have a constant water light. The sending units that i have are the ones i believe i need. Like i said i bought them out of summit and believe they were listed as "sending units" i never knew there was a difference.


These are the ones i bought. Will they work?

http://www.summitracing.com/parts/SMP-TS17

http://www.summitracing.com/parts/SMP-PS149/

 

[Steve73QMach1]

If you have the variable resistance sending unit meant to operate with a temperature gauge, it will not work when using the warning light. If you want to use the warning light - use the switch that goes with it. If you want to use the temp gauge, use the variable resistance sending unit. They are different.

If you have the variable resistance sending unit meant to operate with a temperature gauge, it will not work when using the warning light. If you want to use the warning light - use the switch that goes with it. If you want to use the temp gauge, use the variable resistance sending unit. They are different.

I just looked at your links. The link for the temp sending unit is meant for use with a gauge. The link you show for the oil pressure is a switch that will only work with an indicator light.

This is what you need for your center mini-cluster oil pressure gauge:

http://www.summitracing.com/parts/SMP-PS60/

This is what you need if you want your current temp indicator light to work:

http://www.summitracing.com/parts/SMP-TS36/

 

[mikepasquale1]

Look at the ones i posted from summit. I want to use the gauges. If i have the wrong ones, can you show me the ones i need or the ones you used.

Im thinking i have at least the correct water tenp unit due to the fact that the water light is constantly on.

I appreciated the input.

 

[Steve73QMach1]

Mike - we were posting at the same time - see info above. Keep the temperature sending unit you have for use with your temperature gauge. It is correct. Just keep in mind that it will not work with a temperature warning light. Get the oil pressure sending unit I linked above for use with your oil pressure gauge. The one you have now is a switch and will not work with a gauge.

 

[mikepasquale1]

thanks for the help that would explain why my warning light is on constantly because it's not meant for a light. it's meant for a gauge. I will pick up the oil pressure sending unit that you sent me .that should be readily avaliable at any local auto supply. do you think that I will need that oil pressure sending unit extension housing as well ?. this is going on a 351w.

 

[Steve73QMach1]

You will need the extension for the 351W application. If I remember right, it attaches on the front of the engine as opposed to the back on the 351C

 

[mikepasquale1]

Ya its right next to the fuel pump. Ill get that as well.


So the wires that connect to the sending units connect to the back of the cluster. In other words, they are the same color from the sending unit to the cluster harness? And i can reroute them over to the gauges? Just want to make sure i got that correct. The wires that.control the lights will now connect to the gauges