Thursday, November 5, 2009

Headlight Failure Forces Car-Time

Last night I had to work on Lucy. Somehow it’s easier to break away from house-work and get myself out to the garage when a debilitating ‘vair issue. This time it was the headlight circuit. I only had high-beams. Since my commute starts in the dark and ends that way, I need properly functioning road illumination. Lucy’d had this problem before – a weak connection at the hi-beam switch, so I knew right where to attack. After separating the connector plug from the jack, I tested the switch to verify it’s proper functioning. All was good there. Then I cleaned the terminals of the switch and the mating surfaces inside the plug body. After applying some bulb grease to try to protect the metal from corrosion, I slid the plug back on. No headlights. Irr. I found, however, that if I twisted the plug slightly contact was made. What was happening was the plastic plug body had melted with the high resistance of the corroded contacts. The two contact surfaces were then not held tightly to each other. A small wood wedge behind the plug forced it into properly applying pressure and reliable illumination resulted.

On my way home from work I had stopped by the auto parts store and bought a package of dash light bulbs to replace Lucy’s dim ones. After fixing the headlights, I replaced the old with the new. What a tremendous difference!

When I first put Lucy on the road, the dash lights would not go on. The problem was the circuit in the headlight switch that controls the brightness of the dash lights. The variable resistor was broken. At that time I bypassed the switch by connecting the dash light’s circuit directly to switched 12 volt at the fuse block. That meant the dash light were on whenever the car was on rather than just when the headlights are on. So my next, and last, task of the evening was to replace the switch with the used one I’d removed from the red 4-door. The first step in making this swap is to remove the knob shaft from the switch assembly. This is done by pressing a small button on the assembly while pulling the knob out. When I did that to the assembly in the car, the headlights turned on, so I used the shaft to move the switch to the OFF position. Before mounting the replacement switch, I did the same thing. After tightening the nut holding the switch to the dash, I tried installing the knob shaft into the switch. It took me quite a few tries before it would fall into place. When it did, something was wrong. The knob would only pull out slightly – not even enough to get to the first detent. I tried to remove the knob shaft, but to no avail. I ended up prying the shaft from the assembly breaking something inside. Out came the switch assembly and to the workbench it went. I disassembled both the old and the replacement switches and swapped out the broken part with the one from the old switch. I then put it all back together, tested it, and installed it; this time leaving the switch in the first detent position instead of the OFF position. The knob shaft installed easily and the switch actuated properly. Job completed, but I sure made it harder than it needed to be.

No comments:

Post a Comment