Bradness
New Member
I have an issue with the lighting circuit when I turn on the headlights or dim the lighting circuit. With the headlights in the ON position, my gauge cluster acts up primarily on the left hand side. The backlighting does not work, nor does the cruise control, tach and other accessories. Using the interior dimmer (pot) to dim the overhead courtesy light also causes these same symptoms to appear. The dimmer runs through a relay and I am wondering if either of these components is the problem or I have a short in the wiring. I have the wiring diagram and circuits 14 and 19 appear to be the possible culprits. I know that the dimmers can be a problem. This is an intermittent problem and I would spring for a new dimmer, but they are over $100 (NPD) and I would like to be certain that is the problem. I have the dimmer relay already. My Mustang is a one owner 1989 LX Sport. Comments or advice?