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Resolving (for now) my latest electrical gremlin


OlGeezer

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This past weekend, I dove into the search for the "gremlin". Thanks to Will of Colorado, Twisty, Phil C., Jim Bud and my big sister Carol for guidance and tutelage.

 

I started by testing all of the fuses, ignoring the visual test and going right to the continuity tester. All of them passed. I then tested all of the relays. I connected a 12V lantern battery to the two obvious power pins. This event was validated upon hearing the "clicking" of the relay. At this point, heretofore I would have thought the relay was good based on being able to get it to click. Read on. I then put my Digital Multi-tester across the two remaining pins. The goal was to read zero ohms resistance with the power connected. I would then remove the power and test the same pins looking to get infinite resistance or an open circuit. This occurred on all but two relays. On the ABS relay, I got the opposite results (zero resistance at no power, infinite resistance at 12V), but I believe this is consistent with the wiring diagram on the side of the relay in that the power actually opens the circuit on this particular relay. Someone can correct me if I'm wrong, but I don't have an ABS fault on my display, so I think my ABS is working fine. Of course, there is another way to test it which is more fun anyway. On the final relay, it tested infinite both times. That was my lighting relay. I replaced it with a spare I carry.

 

I then started to look at what I thought was the culprit, my fog light switch mounted on my dash. I hate removing the dash, mostly because I hate removing the windshield because I invariably damage those (expletive deleted) $4 rubber washers at the four attach points. I removed the switch to find a significant amount of crud around all of the connections. In 20/20 hindsight, I wish I would have performed a voltage drop test with the switch in this condition, but I did not (nor did I want to blow another relay). I cleaned the connections and the surrounding area with electrical contact cleaner. That's when I performed the voltage drop test and on each circuit (the switch illumination circuit and the power circuit), the voltage drop measured much less than 0.1V. I then applied a light coat of dielectric grease on the connections and put the dash back together with the now-crunched (expletive deleted) $4 rubber washers.

 

Now was the moment of truth. I turned on the ignition and then turned on the fog lights. Viola! All systems go! The relay terminal at the lighting relay does show some distress, but the contacts still appear shiny (not burned). I believe at some time I would like to replace this terminal.

 

It was only after the RT appeared to function correctly did I decide it was worthy of bug removal from my recent 2,500+ mile weekend. Yeah, I also added a little oil. Call me "old softy".

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