68 F-100 gauge lights issue - HELP PLEASE!

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slucent
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68 F-100 gauge lights issue - HELP PLEASE!

Post by slucent »

Hi yall! - I am wondering if ANYONE out there can help me with a wiring problem. I have a 68 F-100 with manual steering.

Here is the issue:

The Lights in the gauge cluster went out last week and I cannot figure out why. Not - ALL of the lights - Just the ones that come on when you turn on the headlights - the backlighting for the speedo, temp and gas gauges.

The headlights work fine. The Heater and cigar lights both come on when you turn on the headlights and both Dim correctly when you adjust the dimmer switch. The Dome light also comes on with out a problem.
The ACC Light comes on when you turn on the key to Acc. Both Turn signal lights work fine as does the bright-switch indicator light. The Problem is that the lights behind the speedo, the gas and the temp gauges will not come on at all when I turn on the headlights.

I have replaced all the fuses, replaced the headlight switch / rheostat unit, All the lightbulbs - Still nothing.

Basically they worked fine until I was driving one night last week and noticed them shut off. I parked and engaged the E-brake and when I released it, half of the lights came back on. Then - they all shut off again a few seconds later.

I have some wiring diagrams that don't show anything close to what I need. I have a shop manual for the 68 on CD - but it leaves out wiring completely. I am stuck!

Should I just start completely undoing the wiring harness and trace each individual wire from the back of the gauge cluster to the end?

ANY Help will be WONDERFUL!!
Thanks Yall!!

You can post here - or E-mail me

Steve

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re: 68 F-100 gauge lights issue - HELP PLEASE!

Post by bluef250 »

If the heater and cigar lights are working you have power to the dash. If not, check to see if you have power at the 2 amp fuse. Then, check to make sure the ground is good. Remove the connection and clean. Then check to see if the new light bulbs are burned out. The 67 schematic is close (doesn't show the heater panel light).

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Re: 68 F-100 gauge lights issue - HELP PLEASE!

Post by FORDification »

slucent wrote:...Should I just start completely undoing the wiring harness and trace each individual wire from the back of the gauge cluster to the end? ...
No, nothing that drastic is necessary. The instrument cluster illumination bulbs are powered by a light blue wire with a red stripe that runs from the headlight switch up to the instrument panel. Just check to make sure that wire is making contact at the switch, is making good contact at the main harness/instrument panel connector, and that it's not broken in between.
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re: 68 F-100 gauge lights issue - HELP PLEASE!

Post by rjewkes »

:yt: Had my running light wire come loose at the switch a couple of times.
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slucent
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re: 68 F-100 gauge lights issue - HELP PLEASE!

Post by slucent »

WOW! Thanks for the fast replies!

OK - So I will follow the Red/Blue wire from the switch to the cluster harness connector, and then all the way back through to the actual cluster? Or will it pretty much end at the Truck side of that harness connector? It appears that each of the lights (and I think there are 4 of them) that illuminate the gauges when the headlights are on, has it's own wire that runs directly into the Cluster side of that Harness connector. That is appearance only of course - Do all of the lights for these specific bulbs wires run until they are spliced together into one, before they run directly into the harness connector and then onto the switch via the Red/Blue Wire?

If that makes no sense - PLEASE tell me!

Gentlemen, PLEASE excuse my silly questions - I am VERY new to Any sort of wiring, short of unplugging and replugging items

- I appreciate every bit of advice possible!

Thank you again!
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re: 68 F-100 gauge lights issue - HELP PLEASE!

Post by slucent »

How do you go about uploading Photos to a Post? Do they have to be links only?[/img]
1968 F-100-360ci-C6 Auto-9" rear-Eddlebrock 4 bl and intake
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re: 68 F-100 gauge lights issue - HELP PLEASE!

Post by 71 LONG BED »

Keith is ironing out some troubles he's been having with the site lately. Hopefully you'll be able to post pics soon. :D
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re: 68 F-100 gauge lights issue - HELP PLEASE!

Post by FORDification »

The wire goes from the light switch up to the cluster connector. At the cluster it branches off to all the lights via a splice in the wrapped-up section of wiring.

More than likely the wire is loose, dirty or simply not making a connection at the switch or the cluster connector. However, it wouldn't hurt to use a multimeter to run a continuity check on it to check for breaks.
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re: 68 F-100 gauge lights issue - HELP PLEASE!

Post by slucent »

You guys are Great! Thanks for all of the help!
I am however an idiot! HAHA it appears that I replaced ALL of the dash lights before I had the issues with bulbs that were entirely too bright. I didnt even Check them before I started freaking out about wiring because I had just replaced them! Well, Now I have replaced them with the Dimmer Bulbs with the "52" designation and the copper base, and everything works PERFECTLY FINE.

Now - A new problem! I have a small indicator light on the bottom left side of my dash right above the E-brake release. It says BRAKE in the middle. I cannot find this in my manual ANYWHERE, but I assume that this is an E-brake "Engaged" signal light. Problem is that it does not come on when the Truck is on and the Ebrake is on. And yes - I have checked that the bulb is still good.

Any Ideas?
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re: 68 F-100 gauge lights issue - HELP PLEASE!

Post by FORDification »

Your question has been answered in the other thread. For future reference, it's preferred that you keep one problem per thread, to make it easier to find for others searching.
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-> Posting and you! <-a MUST watch for all!!
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