Took the CC instrument cluster out and cleaned it all up, checked the bulbs, and wiring, etc. Looks much better now. It appears I have all the gauges and lights working with the exception of the instrumentation lights (the lights that come on when you turn your running/headlights on). I checked the circuit to the light switch - its OK. OK to the fuse box. Had to replace the instrument cluster fuse (with dome light fuse), and now I have 12V going through the fuse when the light switch is pulled out. However, none of the lights in the cluster light up. I've checked the bulbs and they are good (2 inst. cluster lights, 1 fuel guage illumination light and 1 oil pressure gauge illumination light). But even running 12V to the inst. light harness side of the fuse box does not send any 12V to any of the lines? What could be wrong?? Do I need both inst. cluster fuse and dome light fuses to be OK and installed? The '66 Wiring Diagram shows the code 19 wire (blue - red stripe) going from the light switch to the fuse box and then directly feeding the instrument cluster, and everything looks right and circuit checks out to the fuse box but nothing to the bulbs.

Thanks for any insights into this one.
dagger

 

Does your dome light work?
Do you have continuity between the fuse block and the light switch?
Do you have continuity between the fuse block and the bulb sockets?
What size fuse do you have in there?

 

Rotate the light switch. Sometimes I have to move mine a little to get the lights to come on.

John

 

zombie - no, the dome light does not work and I have not trouble-shooted that circuit yet. I have continuity and power from the light switch to the fuse block, but no continuity from other side of fuse to the dash lights (and I can't figure out how that could be). All the wiring goes into the harness and there is no major cuts in the harness (just wires/harnesses that come out of it and the previous owner did something to them). The rear dome looks to go to a different circuit/harness, but could the two circuits be coupled together somehow requiring both to work or neither? I'm baffled - the factory wiring diagram doesn't show anything special like that.

John, I did rotate the light switch from end to end and no effect.

Thanks,
dagger

 

I was thinking that the switch could've been shorted between the inst panel lights and dome light. Still a possiblility but if you don't have continuitiy from the fuse block to the inst panel sockets???

You should goto Home Depot and get a LAN tracker or wire tracer or fox and the hound (all 3 are the same...just depends on who you talk to). Should be in the electrical section in a locked glass case. $39.99

You hook the main unit to the wire and it sends a signal along the wire. The tracker will allow you to figure out where the wire goes.

Comes in VERY handy when someone has hacked your wiring...I've been tracing wires for 3 weeks now Stupid p.o. before me hacked up the wiring bad

 

A multi meter to check resistance and voltage in wires, along with wiring diagram. I find to a good way to track down shorts and opens in wires.
BB1

 

BB1- that's what I've been using (wiring diagram + multimeter). I like the idea of that signal tracer zombieslayer - but will hold off spending the $$ unless other methods fail.

A question on the dome light: What is suppose to activate it? I don't see any pressure switches in the door jams, so is it suppose to work only by turning the light switch on all the way? I ask this as I was testing the circuits to the fuse box I noticed the dome light was hot. I did have the door open but no switches I could see and the light switch was off (I believe). I pulled the fuse out of the dome light to use in the instrument cluster light fuse station, but that had no effect.

Cheers,
dagger

 

Dagger,

My truck has switches in the door but the headlight switch also has to be turned counterclockwise (anticlockwise) to activate it (wired serially). I intend to change this because the door is hard to open going down the road at 60 mph! A fused wire to the door switch will give me the best of both worlds as long as I don't forget and leave the headlight switch turned to the dome light position and walk off.

 

I think you found your problem and just haven't realized it yet. Previous post said you had juice from the light switch to the fuse block, but nothing on the instrument cluster side of the fuse. If the fuse isn't blown, check behind the fuse block and see if the hot wire from the light switch has came off of the fuse holder or if the fuse holder is deteriated/corroded to the point that power won't conduct through it. There could also be a break in the hot wire from the light switch to the fuse block that could prevent power to the fuse.

 

Possibly that wires are shorted to power, and it is getting power from another source. I would try pulling fuses one at a time until dome isn't hot anymore. If you find that problem, it is possible other wiring problem is at same location.
BB1

 

Success!!

I traced an intermmitent open circuit to the inst. cluster fuse block. Cleaned out the fuse block and spent time cleaning the inst cluster fuse contacts and new fuses and now my instrument cluster lights up (with appropriate dimming from the light switch) like a Christmas tree!!! Along the way I removed the cluster, blew out the 38 years of dust, cleaned it, put it in, broke a bulb, removed the cluster and took it apart a second time, recleaned, and found a reddish marker that was close to factory color on the fuel/speedo/temp needles and recolored them and now it works and looks really good! I also checked the dome light circuit. It is suppose to be hot to the fuse panel, but it is switched on through the light switch (turned all the way up). A clean up there, fuse and a new bulb and that circuit works as it should.

Came up with a little technical work around I'd like to share. One of the little screw anchor spring clips that go on the metal tabs in the dash which is where the 7 screws secure the cluster to were missing (top right). I called a few places and no one repo's it nor did they have any used clips. I was playing with my bucket of nuts/bolts/screws/misc. pieces when I looked at a box of dry wall anchors. Sure enough, I found one that was the right size that could be tapped into the metal tab hole. I then used a screw long enough to get into the anchor and voila - nice and secured instrument cluster!

Thanks all AGAIN for the help and suggestions - much appreciated. Another check mark on the to-do/fix list

Cheers,
dagger

 

You can buy variety packs and individual size slipnuts at Autozone or probably any good hardware store. (if there are any left) There should be something that will work. All of mine are not original. Some look aftermarket.

Also dont forget to plug in the short ground wire to your instrument cluster like I did. Thats right yours lit up. Mine does now. Took me a minute though....

Greg

 

Good job on wiring it pays to stick with it and makes success that much sweeter.
BB1

 

I installed Jamb switches in my truck to activate the dome light when I open the door.
The switches are from a mid 70's Nova. I had to give up the manual activation of the dome light via the headlight switch but I don't need that anyway.

 

Thanks again guys - feels good to solve a problem. Rosati - might consider that option at a latter date - did you hook up both doors to same circuit?

Now on to cleaning up the interior, C6 operation, and installing PS and disc brakes. Wonder what I should do next weekend

Cheers,
dagger