So I yanked out the instrument cluster this morning and this is what I found out...
- The cluster to frame ground was fine but I cleaned all connections anyway.
- I ran a separate ground to the turn signal indicator bulbs and it didn’t change anything.
- I cleaned all light sockets and the bezel frame with a dremel wire brush to ensure good socket to cluster ground, no change.
I am at a loss now. I can remove an instrument bulb from the cluster, turn the headlights on, and just with me holding the bulb socket in my hand the LED bulb will dimly glow. It doesn’t take much continuity to make a complete circuit to light these LED bulbs!
And just to clear some things up I have LED’s everywhere in the car except the glove box light and the shifter light. The turn signal switch is new and so is the headlight switch. I even went as far as taking the turn signal switch apart and jumpered each connection, one at a time, to rule out any cross feeding. The grounds at all four light corners were cleaned and either new ground wires run or jumpers run to prove out existing wiring.
I appreciate the ideas to run an incandescent bulb in the circuit somewhere (which is similar to adding a resistor), but I’d like to get it functional without doing that. Something in these old cars is causing this issue I just need to figure out what.