Electric Gauge Install

I just got a 5" tach and with it I got a electic water and oil temp gauges. My question is, the water and oil temp guages were free and are just the guages(no wiring). I want to install them in a few days, can I just splice them to the stock guages? If so, how? I am just looking for a simple install, the guy that sold them two me said I can just run a wire to the stock harness. Anyone have a good link to a detailed tach install? Let me know what my options are. Thanks.

Im pretty sure you CANNOT splice them to the stock wiring, but the tach, I think you may be able to.

the water/oil temp you cant. did they come with the temp sending units? if not you wont be able to use them unless you purchase new ones

No...I guess he just lied about them. They came free with the tach soooo oh well. What about a good tach install guideline?

What kind of gauges are they (brand)?


The AutoMeter gauges don't come with any wiring either. Not even when bought new .... but they do come with sending units. NEVER use the factory sending unit or wiring to connect an aftermarket gauge.

if its autometer i have an extra water temp sending unit

I'm still away at school but from what my bro told me(he looked at them when they arrived at my house) but he said it's just the gauges by themselves. They are autometer pro-comp guages. Why can't I splice?

they run different voltage or ohms or whatever the sender sends back to the gauge

Ohh....I don't care enough to buy sending units...I'll probably just sell the guages now.

If you would have posted that 10 minutes earlier I would ahve bought them. But I just bought the ones I need on eBay.

If you decide to hook 'em up ....


On the back are letters.

"S" = sending wire
"I" = ignition wire
"GND" = ground

Senders are not that expensive, it doesnt seem (worthwhile if the gauges were cheap).

Ya I understand...but my focus has moved onto saving for a sportbike this summer rather than more parts for the stang

--btw what is the best way to get good instructions on tach install? Calling up the manufacturer? Or is there a good set somewhere online for a mustang install?

There are online instructions out there - AM and other brands have PDF's on their sites.

SImply stated, you connect a key-on power source, ground, lighting and then get a signal from the negative side of the ignition coil to drive the tach. 5-30 mins to wire it up.

Good luck.

If you have an MSD ignition box, you just wire it to that.

I tapped the tach wire for my shift light. I dont know how that would work for hooking up and actual tach though.

my stewart warner tach just connected to the neg coil wire