Electrical issue, instrument cluster, 68 Mustang

[Mark9]

I'm going to have to tackle this small issue, since it drives me nuts.
My left turn signal indicator light on the instrument cluster is always "lit", not fully, but faintly.
When I turn left, it blinks at the normal brightness, but the oil pressure gauge light also blinks.
So, it seems to me that the oil pressure gauge light is somehow hooked up to the left turn signal indicator light.
Anyone had anything like this?
I'm guessing I need to remove the cluster and clean something?
I'd like to have a plan of attack before I start taking things apart.
TIA

[wolfpack]

I have a 68 coupe and have completely rewire the entire car including the instrument cluster. I have the entire car back together and I have the same thing you're talking about with the left turn blinker Illuminating the oil pressure gauge. I have yet to tear it back out and see what is going on

[Franks68coupe]

Check your grounds on the back of the cluster, clean all connections etc. Look up a wiring diagram for your particular year, and try and get everything up to those standards (probably wired just fine, but good to be able to reference). Check your voltages to your individual lights...could also have your ICVR on it's way out back there. If nothing seems wrong there, the TS switch may need a looking at.

[nlareau]

Mine did the same thing until I got all the grounds firmly established.

[frontshadow]

Probably a loose ground wire in the harness. Your old cluster may have been able to pick up the ground (for gagues) if it was screwed in tightly or if the old cluster happened to have a metal fastner touching the back of the gauge housing.

Try taking a length of wire, skin back the insulation on both ends. Then find something solid and clean (like a bolt head) and wrap one end of wire around that. Then touch the other end to the back of the instrument gauge housing. See if that solves your problem. Poor grounding will cause some strange symptoms.

[Mark9]

Originally Posted by Franks68coupe

Check your grounds on the back of the cluster, clean all connections etc. Look up a wiring diagram for your particular year, and try and get everything up to those standards (probably wired just fine, but good to be able to reference). Check your voltages to your individual lights...could also have your ICVR on it's way out back there. If nothing seems wrong there, the TS switch may need a looking at.

I've been using this diagram.
http://hammar.dyndns.org/~djhamma/wiring/1968/E3.jpg
The left turn signal wire is #50, odd that just 1 cluster lamp flashes with the turn signal, when they are all connected to a common wire (#19).
19A is probably the problem bulb.
Looks like the consensus is a bad ground.
I guess I'll know more when I take it apart.