olie05 Posted January 19, 2007 Share Posted January 19, 2007 There appears to be a short in my parking light system. With the engine idling and no parking lights on my voltmeter shows 12.4 volts and increasing across the battery terminals. as soon as I flip on the parking lights the voltage starts to decrease until the engine dies. This does not happen with the standard headlights on, or with any other accessory. How do I go about tracing this short? What should my voltmeter be reading, or what should the resistance be at different points? I feel like a noob right now :/ Quote Link to comment Share on other sites More sharing options...
olie05 Posted January 27, 2007 Author Share Posted January 27, 2007 I spent the day disconnecting harnesses trying to isolate the situation... Somewhere along the line i rendered my lights useless. I'm not even getting 12 volts to the switch anymore! Does anyone have any tips on tracing a short? Quote Link to comment Share on other sites More sharing options...
Tony D Posted January 27, 2007 Share Posted January 27, 2007 If you had a short, it would blow the fuse...ask me how I learned the rear marker lights are not an "idiot proof" plug-n-play hookup! Heavy draw doesn't equate, but there may be a bad ground that causes a big draw where normally it would be minimal. sounds like you are draining the battery with the lights on, and that your alternator is not charging. You should have 13.8V with the engine running at about 2200+ rpm. If you don't see that across your battery terminals, put it on a charger, get the battery fully charged, and then check again. If you don't have 13.8-14.2VDC at the battery when racing the engine above the flash point on the alternator (the point where it self-excites) then your voltage regulator or alternator is kaput. You should never see only 12V on a 12V battery! Counterintuitive, I know, but a 12V should read 13.8V fully charged. Good Luck, Man! Gremlins...it's how they tried to win the war! They put Gremlins in the electrical panels of our B17's. But this Kentucky Harvester..... LOL Forgot to answer your question: find all the points in the circuit that can cause a draw. Disconnect them ALL. Replace your fues with your Ammeter leads so you can monitor the draw on the circuit. Start plugging in each individual connection and seeing if you find one with a particularly big draw. Make notes on which connection caused what draw when connected. They should all add up to what you get when you hook them all in. Same way you find a short, but make sure your ammeter has internal fusing so if you hit a draw above 10A, your internal fuse will pop, and not fry your meter. Most are fused these days, even Harbor Freight and Korean Junk... Again, good luck! Quote Link to comment Share on other sites More sharing options...
olie05 Posted January 27, 2007 Author Share Posted January 27, 2007 thanks! I'm going to check for charging voltage and the ammeter trick tomorrow. Quote Link to comment Share on other sites More sharing options...
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