TenMidgets

Hi All,

I'm a total newbie at installing anything electrical and thought I would give it a shot, but alas I am stuck. Bought a stock clock gauge to replace an aftermarket tach...removed the instrument bezel and unscrewed the bolts around the tach.

Now when I try to find a female power wire to accept the male wire from the clock there is nothing there that fits. I found two orange wires with male ends and another orange w/ a female end that has since been modified and doesn't look stock (I think, who knows)?

I thought the best thing I could do was post some pics up of what I see and maybe someone can tell me what wire will plug into the back of the clock so I can screw it all back on and be done with this?

Thanks!
Bill

matt69olds

GM wiring colors hasn't changed much in 50 years, orange is battery voltage (hot at all times) pink is battery voltage with the key on, gray is dash lighting (power with the lights on changes with how far you turn the headlight switch), brown is power to the taillights. Use a 12 volt test light to check for power on the orange wire. It should have power no matter what position the key is in. If not, check the fuse for the courtesy light (do they work?). Check for power on the gray wire with the headlights on. If not, check the taillight fuse and the fuse for the dash lights. The factory wire connectors have probably been cut to wire up the aftermarket tach. You can use insulated 1/4 spade connectors to replace the ends.

oldspackrat

Iirc, the orange wire goes to the male spade terminal for the clock. There should be a gray connector, don't remember if it's male or female, that plugs into the harness for the two clock lights. This is going off my memory, I'm sure someone will chime in that knows for sure.

TenMidgets

Thanks guys. Unfortunately none of the orange connectors fit the back of the clock. I am way to novice to begin replacing any of the wire ends...maybe my mechanic can bail me out...?

Lady72nRob71

Maybe post a picture of the back of your clock. It should have a spade terminal on it for power...

w31man

From the back that doesn't look like a factory clock at all, maybe that's why nothing is plugging in

TenMidgets

Sure guys...here is the back of the clock gauge showing the factory connection.

@w31man - the one hanging out of the dash is an aftermarket tach I'd like to remove and replace with the clock.

Thanks,
Bill

w31man

Oh ok sorry, i guess i didn't catch that

oldspackrat

The gray wire should be in that hole, probably to the right of it just a little bit. Get a good flashlight & take a good look in there, I believe it is part of the dash harness installed in every car & may be taped to the harness if a clock was not factory installed? I don't see why one of the orange wires will not plug directly onto the spade terminal on the clock??

Lady72nRob71

Factory clock should have a spade terminal on the center threaded stud on the back as seen here.

Your picture was too blurry to see if you have the terminal...
If you do not, you could fabricate your own from a solderless spade terminal and a ring terminal, soldering them together.

TenMidgets

Ok maybe I am starting to figure this out a bit?

Rob - I do have the spade terminal on the back. So does the orange wire go on there? If so, where does the gray wire go?

Sorry I am asking so many dumb questions.

*Edit - tried to plug the orange wires into the spade terminal but neither produced any movement of the second hand with the ignition on. I am out of my league here I think.

ent72olds

Bill, did you take a test light to check for power at the orange wire? Should have constant power to run the clock...the gray needs to connect to switched power with the headlights. You need to find a wire with power only when the headlights are on for the bulbs. If the orange has constant power(batt), and you plug it in and it doesn't work, IIRC, it needs to be grounded, and someone can correct me if I am wrong, but it may ground when you screw it in the dash. To be sure, connect the live orange wire , and use a jumper wire to the body of the clock to ground it somewhere on the dash....

OLD SKL 69

You're right Erik, the dash does ground it. Plug in the orange wire to the spade terminal and put the clock in the dash housing and screw it in. It should start working.

Let us know what happens after you do that.

TenMidgets

Thanks guys - I'll give it a shot! Can't believe I forgot to ground it before testing (doh).

Tell me about the aftermarket tach wiring in there now -- any reason I can't just cut them and get them out of the way so I have more working space to screw in the clock?

Thanks again,
Bill

ent72olds

It looks like the tach was hacked into original wires. You should be able to eliminate the add on wires, just make sure anything that could be live or switched on live is capped so as not to ground out against something. Did the tach have lights in it? If so, that wire was probably the wire to use for the lights in the clock. Just locate that wire, make sure it switches with the headlight switch, and use it. I may have the proper end for you if yours is gone. Or you could make your own. I have some old harnesses laying around that may have a plug....

Lady72nRob71

Many times, the most obvious fault is right under our noses; been there many times myself.
Let us know if that works. If not, make sure there is 12V at the orange wire with key off and that the clock unit itself is good.

TenMidgets

I probably overcomplicated this, but the clock is in and working. But I now can't figure out where to connect the lights. Can't see anything obvious or close enough to connect into the gray wire coming out of the clock.

There was a light in the previous tac and a long thin white wire that ran to the floor which connected into another gray wire which I assume is for the lights, but there's no way to reach it up to the height of the clock, nor do the connections match. Ughhh...hoping there is something closer up to the back of the clock I can connect it to and get lights!

Thanks

matt69olds

Your making this far harder than it has to be. Find a unused gray wire under the dash, most cars will have several in the harness to connect optional equipment (which your car may or may not have been equipped with). Once you have found one, verify its function with a test light, it should show power with the lights on, and dim when you turn the headlight ****. You need to keep in mind, the car is almost 45 years old, who knows how many different tachs, stereos and gages have been installed over the years? The factory connectors were probably cut off when the first person added their first aftermarket customizing accessory. If you cant find a unused wire, find the light that back lights the ashtray and splice into that gray wire.

ent72olds

Bill, did the aftermarket tach light up? If so, use that wire....just check to make sure it works with the headlight switch. You can make your own end for the wire.....radio shack or auto parts store will have what you need in electrical section.

TenMidgets

Thanks guys, I'll keep trying.

Erik - good luck with Matt checking out that 69 vert. Hope it comes thru as a solid car!

ent72olds

Wednesday.....you wanna come?

TenMidgets

I think you guys have it under control, but keep me posted and let me know how it goes!