I've been trying to figure out why none of my gauges or illumination lights work on my 75 914. Only one light on the cluster seems to work. The headlight on (one first click, though) light on the speedo. I've checked grounds, all clean. Checked wires, mostly good besides the tachometer having a 'double' red/white wire instead of one (could that be a problem?). Everything else looks fine and I don't see a reason none of it wouldn't be working besides that one light. Thanks for any insight

What year car? Early cars 70-72 have 911 style bulb wiring, different from later.

Oops. Year is 1975

Bump

According to the 75-76 wiring diagram, the red/white wires also power several of the warning lights. Like the oil pressure light, the charging system light, the low fuel light, and so on.

It looks like there is one daisy-chained wire that powers the following:
- Tach
- Oil pressure light
- Fuel gauge
- Low fuel light
- Alternator warning light

This comes from fuse #9, which has three wires crimped into one connector: Red/White for all of the above, red/white to power one part of the turn signal switch, black/yellow to power center console voltmeter and temp gauge if present and also parts of the taillights.

Gauge illumination power comes from the black/blue wires, which are fed from the headlight switch.

--DD

After all this time is was just two wires on the fuse box switched that caused it not to work! Thank you so much!