Modernizing The Headlight Curcuit And Instrument Lights On A 1965 Ford Mustang Fastback – San Diego, California

     Does your Classic Mustang suffer from dim or flickering headlights? Is it hard to see your instrument gauges at night? It is a very common problem, and there is a solution.  The source of both problems are caused by  the headlight switch. Your headlights, brake lights, running lights, and instrument lights all draw power through the headlight switch, and cause old switches to get warm. The biggest electrical load are the headlights. There is a circuit breaker inside the headlight switch that cycles on and off, and will do it more frequently when the switches get dirty and old. That is what is causing your flickering headlights. The switch is doing its job, and preventing a short circuit, and possibly an electrical failure. The fix is to have the headlights run off of a pair of relays. The relays act as a trigger when you pull the headlight switch knob out. Once that happens, the switch is longer supplying power, and the headlights are getting their power directly from the battery. Since the headlights aren’t using the internal headlight switch circuit breaker anymore, an inline fuse is used between the battery and the relays. Also, it helps to replace the OE style headlights with modern Halogens, and they will get plenty of direct 12 volt power too.  The headlight switch is also one of the causes of dim instrument lights.

     The brightness of the instrument lights are controlled by rheostat wheel on the front of the switch, and they get corroded over time. The one in this 1965 Mustang Fastback was the original, and the green corrosion can clearly be seen in the pictures. To get the brightest dash lights possible, I address the problem three ways. As a side note, instrument gauge clusters are delicate, so great care has to be taken when removing them, and taking them apart. First, I clean the headlight switch plug, and replace the old switch. Second, I repaint the white and black instrument bezel reflector plate with a more reflective paint. Third, I replace the OE instrument bulbs with modern LED lights. This is a guaranteed approach to brighter instrument lights. Plus, the LED’s draw much less power through the headlight switch, so it doesn’t get nearly as warm.

If your Classic Mustang suffers from dim and flickering headlights, or your gauges are hard to see, then give Classic Resto Garage a call at a 619-929-8506, or fill the contact form.

Happy Cruising!

posted by inlinesix in 65-66 Mustang and have No Comments