I am troubleshooting my left rear tail light turn signal. it works with the hazards and turn signal but it does not come on with the headlights (illumination). the right side works perfectly. my grounds are good and I replaced the illumi fuse. has anyone come across and issue like this? Could it possibly be the turn signal CPU?

 

If I'm understanding you properly, your rear left turn signal is operating property. Your right is malfunctioning. The rear turn signals are only on when using hazards or turn signals.

 

Both the right and left work with hazards and when left/right turn signal is selected. When i turn the headlights on, the right turn signal is on solid and will flash when triggered by hazards and turn signal. The left one is not on solid when the head light is on, but it will flash triggered by hazards/turn signals. The asymmetry bothers me....

 

I think you just need new bulbs. They are double filament. You probably have dead parking lamps. Check the bulbs.

 

All bulbs have been replace. It is not a dual filament bulb, it is only a 2 wire socket. So it must be an issue with the right tail light turn signal. I am getting 7 volts on the right with illumination on and 0 on the left. Could there be anything from the cluster sending voltage to the bulb with illumination on?

Previous owner put a non TII cluster in.

 

Yes it has two wires and it powers a dual filament bulb. Check your bulbs to see if you have broken filaments. Why mess with wiring before checking the bulbs? Just because they're new doesn't mean they work. If your lamps aren't dual filament then you have the wrong bulbs.