i have read every blog i can find on dashboard lights not working, including videos, i even have the large paper schematic for 1974 f100 written by aliens, the ones that live inside the moon. i can not determine why i have no connectivity to 3 wires.
i have a new headlight switch, have tried 3 just in case found new old stock all work the same, and the steering column wiring harness is new to the truck, not by me. i managed to fix the horn and horn bar. i have the 2 blue lights behind the speedometer, light at headlight switch and dome light work but, the 4 lights that illuminate the gauges do not have current. the printed circuit on the cluster back has connectivity. 2 of the cluster lights work when i turn on signal lights or hazards but dont work any other time.

i managed to find the 3 wires that should provide current to the 4 lights.
white with blue stripe, white with red stripe and a small gauge purple wire.
i pulled the connector under the dash apart to check connectivity, part A connects to steering column, part B connects to fuse box and other things.
there is no connectivity between part A and B for the white with red stripe or the white with blue stripe but part B does show connectivity for the white with red stripe to the unit, call it part C, that plugs into the back of the cluster. there is a purple wire on part C and i can find no correlating purple wire that i can test, (it is not the one that is connected to the ignition) there is connectivity between the top of steering column wiring and part A, so no short indicated.

on part C where bk/bk-gr is indicated i have black/purple, the purple is heavier gauge than the other purple wire next to the white with red stripe and seems to connect to ignition switch where a black and purple wire are combined.
i show connectivity between the combined wires on ignition and the black/purple on part C.

i do not see an ignition switch color combo like the one on my truck in the schematics.

i have checked all the wire colors with their respective locations on part A and B, with the exception of the black/purple wire connection on part C all wires are as indicated in schematics.

 

Agree with FTZ HAIC. What schematic are you referencing. You seem very adept to what your doing, but I have a few simple questions. These 4 bulbs for illuminating the gauges. I believe they twist in contacting the printed circuit?? With gauge panel removed, have you check for continuity of the printed circuit for breaks not easily seen in the gauge light circuit?? Cap

 

here is link to schematics http://fordification.net/tech/wiring.htm i am looking at page 2 and 3
wiring_master74master_2of8.jpg
at bottom of page
block c-260 14481 with gauges

this block shows all color of wires in respective slots, where bk/bk with green strip is indicated i have a bk and a purple wire combined.

none of the ignition modules on this page match mine, mine has 5 connections in the harness

wiring_master74_30f8.jpg
at bottom of page
block c-305 shows steering column wiring harness, all my wires are as indicated in this diagram

i rechecked printed circuit and there is connectivity to all the bulbs

the blue lights come on when i turn on headlights
the 2 light clusters on either side of the blue lights do not come on but, the 2 closest on the left and right of the blue light flash for signal and for hazard

all gauges work

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Ive looked at the link you've sent. I still need to deal with questions. Talking strictly about Cluster Illumination to use their terms, to me it's dash lights. With headlight switch out, the bulbs that do light, will they go dim to bright by turning the switch knob left and right?? how about the bulb in the PRNDL indicator, apparently there are bulbs to illuminate dash switches. Do all these bulbs respond to dimming and brightning. On this light thing, did you inherit this problem when you acquired the the truck or has this happened since you've owned it?? Have you installed LED bulbs??

Your reference to Ignition Module? Does this engine have Points and Condenser Ignition or Electronic of some type? What engine in truck? Cap

 

thanks for taking time to review this issue, as it turns out the lights not on are for another task, i thought they were supposed to come on when i turned on the headlights but, they are for highbeam and parking break and they work for that purpose. so issue resolved, thanks again

 

Glad you got it ironed out. Cap