dash/tail lights help

ok everytime i use my right turn signal my dash and tail lights go out. it started doin it after i installed a aftermarket tach. i uninstalled the tach thinkin that was the problem. but its still doing it. anyone have any ideas?

The park light, [dash/tail lights] circuit and signal light circuits are two diff. circuits, park lights are on a constant power circuit, [hot at all times] and the signal lights are on an ign. circuit, [hot when ign. switch is in run] so I am not sure why the park light fuse blows when using the signal lights.

Questions…

Is it fuse 11 - 15A, in under dash fuse box that blows?

Does the fuse blow if park lights are on or off or both?

Do the park and signal lights work normally otherwise? 94

well its not blowing any fuse’s they just turn off and back on.

OIC, the park lights go out when the right signal light is on.

Do the park light’s flash off and on when the signal light flashes on and off, or do the park lights just stay off as long as right signal is on?

Normally when one circuit has an effect on another circuit it is because of a grounding issue.

Unplug the rear right signal light bulb and try the right signal, does it still effect the park lights, if not check the ground for the right rear signal light. 94

ok ill try that. if thats not the problem could it be the switch in the steering coloum?

I guess it’s possible that it is the combination light switch, although they are diff. circuits it could be a mechanical issue, as both switches are in the same housing. 94