Hi,

I have a 1981 F100 and a digital clock from the same generation truck. There are two harnesses in the truck to the right of the heater controls, but neither will fit the one on the clock I have.

The wires on the clock are black, white with a purple stripe, light green, and brown. One of the two harnesses in the truck has both black and white with a purple stripe, but it also has green with a yellow stripe and blue with a red stripe.

I have really never done any wiring, and wanted to know how to connect the digital clock. Can I just cut the harnesses off and splice the wires together? If so, what do I need to connect the light green and brown wires to?

 

hope they are some help

 

According to the '81 factory shop manual:

• Ckt 57/black is ground
• Ckt 54/light green/yellow-stripe is +12v and is always hot
• Ckt 296/white & purple stripe is +12v when the key is on
• Ckt 14/brown is power from the headlamp circuit to dim clock

And, to answer your question, you can cut the plugs off and splice in. However, there are two different clocks during those years but, although the connectors are different, the wires themselves are the same. (ed: May not be true, see below.) What I did when I put an '85 clock in my '82 truck was to take the terminals out of the connector and plugged them into the appropriate hole in the truck's connector and wrapped that with tape.

 

Is it really that easy Gary? I already have a non-working 80-82 clock, so if it's that easy, and the metal terminals are the same on both clocks, then I'll just insert the 83+ clock terminals into the 80-82 connector.

 

The clocks are not the same...

1980-1982 uses one type of clock.

1983-1986 uses another type.

The differences between the two clocks is how the backlit display dims, and some cosmetics on the front display and buttons.

On the 1980-1982 the dimming circut uses a dimable backlight that is controlled with the headlamp switches instrument cluster dimmer. It is the same circut that lights, controls and dims the instrument cluster. (Light Blue/Red Stripe) On this clock you can adjust how much the lamp dims, although it only dims slightly more.

The 1983-1986 clock uses the brown wire (which is the same as the parking and tail lamps) to dim the backlight. (On this clock the lamp is either full bright or full dim).

This is why the connectors are different between the two clocks.

HOWEVER: If you want to put a 1983-1986 clock in a 1980-1982, all you have to do is get the connector from the main harness, along with the clock harness and plugs from the 1983-1986. What you will want to do is remove the connectors off of your trucks main harness with a tool of some kind. A precision screwdriver will work. You need to remove the red wire keeper from the connector. Then you can remove the wire terminals one by one from the two seperate connectors on the 1980-1982 and transplant them into the new single connector that you got from your 1983-1986 donor vehicle. DO NOT CUT ANY WIRE, it is not nessecery at all to cut them. Just match the colors of the wires to your clock harness and you should be fine. Once the wires are transplanted keep the old connectors if you want to switch them back. (Don't forget to replace the red wire "Keeper".

If this truck is a show truck, you may lose points for not having a year correct clock, but for a daily driver it is totally acceptable.

The 1980-1982 version is also better made and will last longer than the 1983-1986 version. The buttons on the 1983-1986 are prone to stop working or be very hard to press to make the functions work and is made out of plastic. The 1980-1982 version has a metal backing, and the buttons work better. They also have different setting proceedures.

(On a side note Fordzilla80; have you taken your clock apart to see what was wrong yet? I'm thinking it might be the bulb inside for the display. Although how big or small the bulb and if you have to use a soldering iron to replace it, not sure. If I remember rightly the tests we did, you could see an outline in the display with it on, but it wouldn't light. (If I Remember correctly. It's been about a year.))

 

You have a good memory! I can see the numbers when I shine a light into the screen, but nothing shows whenever I turn the truck on. If I recall correctly, I pulled the light apart and ran my test light through all the connections onto the circuit board, and it seemed that every connection that should have power had power as they made the test light shine.

 

I'll have to find one in the junkyard and take it apart and find out about the backlight in more detail.

If I see one of the older type, they are the more rare of the two, unfortunately.

Look in broncos as well. They used the same clock year for year with the F-series.

 

I have mine apart right now, and it looks like the circuit board is held onto the face plate with little rings that I guess hug the face plate posts. I can see what looks like a really tiny bulb that comes out of the side of the back light, but I need to remove the face plate first to get to it.

 

While the process Explorer outlined is the best way to put a newer clock in an older truck, or vice versa, it is possible to remove the connector from the clock and stuff the pins into the truck's connector. IOW, take the pins out of the clock's plastic connector, since it won't plug into the truck's connector, and insert each pin into the truck's connector. Then wrap that with tape to ensure the wires don't pull out.

It is really that easy.

 

Added to the Sticky:

https://www.ford-trucks.com/forums/8...ml#post7434560

 

Be extremely careful!!

The faceplate is easily damaged as it uses polerized glass and liquid crystal to change the numbers. easily damaged.

The earlier 1980-1982 clocks use a liquid crystal display with a backlight, which I think on yours the backlight is burnt.


The 1983-1986 use a LED Display.

 

I'm not sure what it would look like burnt, but there is a black spot in the bottom right corner of the polarized glass. This is right below there the little bulb looking piece is. As for the back light, is that below the polarized glass?

 

Wow, I was never expecting such a response from everyone. I did what a few of you guys recommended and just cut off the plug on the clock side. Tonight, I went and hooked it up to see if it works and it did.

Perhaps somebody could explain how to program it? When I hit "Date", all I get is two vertical lines. "E-Time" begins counting up from zero. "Time" displayed 12:00. How do I go about setting everything up? I assume the two smaller buttons have something to do with it.

Thanks, fellows.

 

There are two pieces of polarized glass to make that display work

The black spot could be the liquid crystal and the display is damaged, or just a burn mark from the bulb; but can't really tell without seeing it.

You shouldn't be able to see characters though with your flashlight if it was the display and not the bulb. Or you would see all 88:88s lit up.

.

On certain LCD displays (the most comon actually) the characters are displayed on a mirror like surface. On these displays you only need an external light source such as a room lamp or the sun. Some have a lamp that reflects light off the mirrored surface. This type of display uses a mirrored field and the characters are black. 88:88 as example or black on white paper like this text. The mirrored surface gives the field contrast. Used in cheap calculators, cheap digital watches, and cheap gas pump displays. The liquid crystal is energized to make the numbers.

On other more expencive LCD displays like your trucks 1980-1982 clock, the field is black, and the characters are clear or see through. The backlight shines light through the characters so you can see them. In other words when the clock wants to show you the number 1. It blocks part of the number field "that looks like an 8" with the black liquid crystal and leaves the part that makes the number one clear. So the clock energizes the part of the character to make it black so the light doesn't shine through it. Like clear cut out text on black paper as a example. Without the backlight shining through the characters the display remains dark. Not really used much anymore with the evention of LED displays.

Now LED displays are better designed. Each section of the display that makes up the 88:88 has it's own LED light or 7 small LEDs to make each 8. To make the characters it turns on or off a section of the character. As example to make the number one it only lights the first two led lights on the right. To make a three it lights the three center lights as well as the first two leds it used to make the number one.

Now the 1983-1986 clock either uses the LED display system, or it uses a LCD display with a LED backlight. Not sure which as I havent had one apart.

 

1983-1986:
There are two round small buttons on the right hand side.

To set time: push the time button at the same time as you push in the left hand round button for hours, right hand button for minutes...

To set Date: -Push the date button while simultaniously pushing the left hand small round button for Month. Push the right hand for day.

The E-Time is also a stop watch. When on E-time push the small buttons to either reset the e-time or to stop the e-time.

1980-1982:

Almost the same as above except:

Pull out the Time button as you would to set stations on a old push button radio. Then take a pen to the two recessed buttons on the right that is labled reset in raised black letters, to set Time. Push back in the Time button when finished. Set the date the same way.

To reset the E-time pull out the E-time button when the clock is in time mode. To stop e-time push the recessed button with a pen when the clock is in e-time mode. Push the E-time button to switch modes between E-time and time. When the truck is off, press the date or time buttons and the clock will show either date or time while the button is pressed.


Hope this helps.