Looking for a little feedback and assistance with and electrical issue. I removed the instrument cluster from the dashboard to repair some dash lights that were malfunctioning and determined the grounding of the PCB was weak or in need of improvement. I rigged a grounding harness by using four contacts in a series with the PCB mounting bolts and grounding the whole thing to the dash frame.

I began to reinstall the instrument cluster and wanted to run a check to make sure the dash lights were all functioning before wrapping up. Turn signals were great, high beam was great but there was no dash lights at all. Then I realized there was no passenger dome at all. For that matter no running lights..I lost a number of light systems all at once.

I checked the light switch with a circuit tester and found that the only outgoing terminal with any juice is for the headlights. The "H" terminal.
All the others (5 terminals) have no output. I figured the switch was bad and bought a replacement and it does exactly the same thing so I don't think it is the switch. I checked the fuse box and found a bad fuse in the #2 slot (brake light) I replaced it but that did not help. There is no juice to the #1 slot on the fuse box but I am thinking that is should originate from the light switch. Is that incorrect? I am out of ideas at this point. Could a grounded line affect all these terminals? Please share your thoughts, ideas or speculations with me. Thx and Merry Christmas

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more info

here is the light switch
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here is the grounding harness
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http://i1036.photobucket.com/albums/a44 ... e9iecf.jpg

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Vehicle rear lights + dashboad lights + dome lights are on one fuse so that if you lose your rear lights, you'll have an in-car indication there's something wrong. Figure out what blew that rear light fuse and fix it. Dashboard lights won't illuminate unless the cluster is grounded, which it usually isn't when it's not installed, since it gets its ground via the dashboard metal.

If you have output from headlamp switch H, then the one and only input (feed) to the headlamp switch is intact. Problem (or appearance of problem) could be in multi-wire connector that snaps onto headlamp switch.

While you are at it, here's a safety upgrade worth doing: On (most) pre-1968 vehicles, including yours, the parking lamps do not remain lit when you turn on the headlamps. For 1968, this was changed so the parkers stay lit with the headlamps for safety (in case of a headlight burnout you still have at least some visible light on the burned out side of the car, so oncoming drivers can still see your car's width and not mistake you for a motorcycle). This is easy to retrofit: remove the headlamp switch and unplug its multi-wire connector. Put a short piece of 18ga wire from the "P" to the "R" terminals on the headlamp switch body, right down at the base of those terminals. Make sure the ends of the jumper are neatly tucked so they won't touch any adjacent terminals. Solder if you like. Then push the connector back onto the switch, on top of your new jumper wire which won't get in the way, and reinstall the headlamp switch. This will emulate the wiring setup of '68 and later cars that keep the parking lamps lit with the headlamps on.


Nice grounding harness you made.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

And disconnect the battery before you start screwing around with the headlight switch...............

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

Thanks for the feedback. I was wondering about the running lights dropping off when the headlights went on.

I was trying to figure this out last night and wound up taking the light switch and only attaching the power source to B1 (all other wires removed). Using a circuit tester (the pointy rod with a light in the handle) I was able to only get a circuit on the H post (headlights).

Shouldn't I be able to get a light from the other posts when I pull the switch to the first or second click or am I not thinking this through correctly.

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Oops, sorry, I believe I misinformed above. Multiple feeds, not single.

B1 feeds power to H (when the switch is pulled to the second click) to the headlamps via the high/low beam kickswitch.

B2 feeds power to R and P for the tail and park lamps (when the switch is pulled to the first click).

I is powered via the instrument lights fuse, feeds power to D via the rotary rheostat for variable-intensity dashboard lights.

With the switch off (pushed all the way in) look for power at B1, B2, and I. If not, you've got wiring work to do.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Making some headway. Found a loose connection at the fuse box and now have restored power to B2 terminal (P and R) are back online.

Still don't have power to I terminal. checked the entire loop. Tan wire from D to the fuse panel. Orange wire from fuse panel to dash and steering column checks out ok. The yellow circuit back to terminal D seems complete since the dome light works when the car doors are opened.

Does the power for this loop generate from the switch?
B1 and B2 come essentially from the battery but isn't terminal I just an extension of the switch? That being the case does this imply the internal circuit in the switch is the problem.

Getting closer

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Am I looking at this backwards. Dan, you said terminal I is powered by the instrument light fuse. That would be the orange wires coming back into the fuse box.

Does that mean that this circuit is only functioning when I have the instrument cluster grounded so as to provide electricity for this loop?

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I think you're on the right track -- try either installing the instrument panel or running a test lead from it to ground.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

I hope this will help someone down the road with a light switch problem. It turns out that I have poor connections on the fuse box in both the #1 and #2 slots. I bridged the second slot of the fuse box with and inline arrangement for the red-tr to pink wire which gave power back to the B2 pin on the light switch. The fact that the "I" terminal was lacking power was due to a second short at the fuse box between the tan line which leaves the switch and the orange wires that exit the fuse box to light the dash. Once this was bridged with an inline arrangement the issues have been resolved.

I think the difficulty in figuring this out was due to the fact that the fuses were intact but the end connections were faulty. I would get a positive read on the fuses but it did not carry through to the connections coming out on top. Good luck to all with electrical issues

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