Aftermarket gauge wiring

[tuhockey11]

Havent done this in a while on a Mustang...I know I need two separate ground wires for the bulbs and gauges, Im assuming I can wire the positive from the gauges to the radio switched 12v source. My only question is, where can I wire the gauge bulbs to so that they will turn on/off with the lights as well as dim? Is there a wire in the radio harness for dimming? If not, wheres the easiest place? Gauges are going under the radio in a pod and its a 92 GT...TIA

 

[SuperStang83]

Autometer.com has diagrams on their web site.

 

[HISSIN50]

The radio harness might have an illumination circuit. On earlier cars it was orange with a tracer (can't recall the color. White perhaps). If you find a candidate, just test it with your test light (as you run the dimmer down, the test light will dim).

You can also tap into the illumination for the HVAC controls (since they're close-by). Or tap into fuse 13.

Good luck.

 

[tuhockey11]

Helpful as always guys, gauges work great. Using the new VDO vision gauges with the green backlight, look great with the stock gauge and HVAC green lighting

 

[65ShelbyClone]

You can also tap into the illumination for the HVAC controls (since they're close-by). Or tap into fuse 13.

That's what I did on my '89GT because I didn't want to poke holes in the harness with taps. I used the type that fit under the fuse and have a spade connection on the other end.

 

[tuhockey11]

Ended up using the dimmer wire from the radio, very convenient as it was not being used with my aftermarket radio. I have a few questions about the gauge readings though. Water temp is fine, but oil pressure starts at 60 cold and goes to 40 hot. In my previous expereince with decent gauges, it should go down to about 20 psi at hot idle, correct? Also, the voltmeter is reading 14 with headlights on, this is a stock 5.0. Didnt think it would be that high. Also the factory gauge decided to read higher than before after the install.

 

[65ShelbyClone]

40psi hot at idle is good pressure.

 

[HISSIN50]

Check your grounds if you think the gauge readings are off. And check them against other known good gauges (i.e. you can check your voltmeter with your DMM).

Good luck.

 

[SuperStang83]

Your oil pressure is good, and with the car running you should have right around 14 volts at the battery.

 

[tuhockey11]

Gauge grounds are definately good. Cleaned them up very well before install. The readings arent that abnormal, i just thought it was wierd that the factory voltmeter started to read higher after the gauge install. I didnt do anything that would affect the wiring to the factory gauge.

 

[Black1987Stang]

Like Hissin said check it with a voltmeter and that should be the exact voltages and compare with the gauge, you can also ohm out any grounds to make sure theyre making full contact if you want to be sure.