How to: Installing gauges in 1995 Mustang GT.

ttocs · Sep 22, 2023

you could have used the orange wire behind the radio to supply the dimmer control and then the gauges would probably dim with the stock gauges as you adjust the headlight knob.

maillemaker · Sep 22, 2023

ttocs said:
you could have used the orange wire behind the radio to supply the dimmer control and then the gauges would probably dim with the stock gauges as you adjust the headlight knob.

There is a whole radio harness in there. I thought I was going to be able to tap it for power, key on power, and ground, but when I put a meter on them everything was dead. I didn't pull the previous owner's head unit so I don't know what's actually going on in there. I gave up and pulled my own runs.

ttocs · Sep 22, 2023

yea realistically you could probably power the gauges off of those power wires(if working) short of an AFR gauge, if they are working. Those can pull a little more current as I believe they heat the sender for a short time during warm up. If the radio works there is power/ground and you must have not been measuring something right.

maillemaker · Sep 22, 2023

The radio works but must not be plugged into the legacy harness.

ttocs · Sep 23, 2023

what is a legacy harness?

maillemaker · Sep 23, 2023

The factory radio harness. Or maybe it is for optional cd unit. Can’t see what aftermarket head is plugged into.

ttocs · Sep 23, 2023

if it works and you have sound from the speakers it sounds like it is connected to something. Depending on what system came in the car it might have a few different/extra harnesses but the main power harness is the same with all of them.

maillemaker · Sep 24, 2023

Pulled the gauges out today and re-wired the volt gauge directly to the Battery + so it now reads actual alternator output not what the isolated DC-DC output is.

While I was in there I pulled out the factory radio harness (I assume that is what it is):

I'm not using it so I just stuffed it back in out of the way.