Dash / Instrument Lights Problem Unresolved Options

[JimVG]

I have researched this problem on this site, and I still cannot correct the issue of no dash/instrument lights on a 1973 914.

The Problem
When key is ON, and the headlight switch is in the ON position none of the instrument light bulbs illuminate. Turning the headlight switch dimmer has no effect. All fuses tested functional.

Testing Procedure
Using a test light that is properly grounded with the headlight switch ON and the dimmer turned to HIGH:
There is no power to headlight switch terminal 58a or 58b (Fuse #7 is functional).
Using a separate test wire with a working bulb connected to headlight switch terminal 58b and the opposite end plugged into an instrument bulb socket the bulb does not illuminate.
Using the same test wire connected to terminal headlight switch 56k (empty and has power) plugged into the same instrument bulb socket the bulb does illuminate (dimmer not functional).

Please advise.

Your time and consideration is appreciated!

[emerygt350]

I would suspect your switch dimmer is bad. I pulled mine and just bypassed the dimmer. New switches can be purchased I believe. If you pull the switch you can test it by sending 12 past the pot.

[ClayPerrine]

I would suspect your switch dimmer is bad. I pulled mine and just bypassed the dimmer. New switches can be purchased I believe. If you pull the switch you can test it by sending 12 past the pot.

(IMG:style_emoticons/default/agree.gif)

The potentiometers are notorious about failing from age. Simple to bypass it and just wire the instrument lights to the park lights.

[barefoot]

I would suspect your switch dimmer is bad. I pulled mine and just bypassed the dimmer. New switches can be purchased I believe. If you pull the switch you can test it by sending 12 past the pot.

(IMG:style_emoticons/default/agree.gif)

The potentiometers are notorious about failing from age. Simple to bypass it and just wire the instrument lights to the park lights.

For my 76, the instrument lights do come on with parking lights, key off.
BTW all are changed to LED's now I can see much better.
Barefoot

[JimVG]

I would suspect your switch dimmer is bad. I pulled mine and just bypassed the dimmer. New switches can be purchased I believe. If you pull the switch you can test it by sending 12 past the pot.

(IMG:style_emoticons/default/agree.gif)

The potentiometers are notorious about failing from age. Simple to bypass it and just wire the instrument lights to the park lights.

For my 76, the instrument lights do come on with parking lights, key off.
BTW all are changed to LED's now I can see much better.
Barefoot

Thank you for your replies. I would like to bypass the rheostat. Is there any reason why I cannot connect to another blade on the switch that powers the parking lights? I believe that this would allow me to have instrument lights on when either the parking lights or headlights are on.

[emerygt350]

I would suspect your switch dimmer is bad. I pulled mine and just bypassed the dimmer. New switches can be purchased I believe. If you pull the switch you can test it by sending 12 past the pot.

(IMG:style_emoticons/default/agree.gif)

The potentiometers are notorious about failing from age. Simple to bypass it and just wire the instrument lights to the park lights.

For my 76, the instrument lights do come on with parking lights, key off.
BTW all are changed to LED's now I can see much better.
Barefoot

Thank you for your replies. I would like to bypass the rheostat. Is there any reason why I cannot connect to another blade on the switch that powers the parking lights? I believe that this would allow me to have instrument lights on when either the parking lights or headlights are on.

I believe that is what I did as well.

I also put in all leds on the dash except the oil and gen lights.

[JeffBowlsby]

Circuitry for the switches is here:

https://bowlsby.net/914/WiringHarnesses/doc...ashSwitches.pdf

[JimVG]

Circuitry for the switches is here:

https://bowlsby.net/914/WiringHarnesses/doc...ashSwitches.pdf

Thank you, Jeff. I found your previous posts. My car is a 1973 with an 11 blade switch as shown on your 1974 diagram. I attempted to simply bypass the rheostat by connecting together the wires that were on 58a and 58b as you have suggested, but that did not illuminate the instrument lights.

I am not concerned with restoring the dimmer function. What headlight switch terminal would be best to take power from that would allow instrument illumination when the parking lights and/or the headlights are on and still be a safe connection?

I have read where others attempting this have had electrical problems (blown fuses and under-dash fires), so I want to insure that I am avoiding that possibility at all costs!

Thanks again!

[JeffBowlsby]

Do you have power at 58b? You should, and if so, the lights should work. If not, chase the power circuit upstream until you find the issue. Use the wiring schematic to see how it all works.

[JimVG]

I used a "Power Probe III" to trace the problem back to the fuse block.

Thanks again, Jeff, and all others who replied.