RebekahsZ Posted July 24, 2012 Author Share Posted July 24, 2012 Another stupid question. I see some test light probes that are sharp enough to poke thru the insulation into the wire. What's the party line on that? Is it ok to poke thru the insulation, or do you guys always go to the end of a wire segment at a connector to check for voltage/continuity? I'm betting it is gonna be a connection, I'll find it or be damned! Yep, checked bulbs. Hazards work. Quote Link to comment Share on other sites More sharing options...
bjhines Posted July 24, 2012 Share Posted July 24, 2012 (edited) You can remove the corner marker lights and unplug the bullet-connectors to eliminate them from the system. There could still be an internal short in the light housings, so completely remove all the corner marker lights. While you are at it, clean up any rust, repaint the areas and put new slip nuts on the body then rub some vaseline on it all and install brand new corner marker lights all around. On my 240Z the green/blue from the fuse goes directly to the light switch The switch output is green/white and feeds all the lights the rheostat has green/white input and red/blue output to feed the dash lights If you unplug the rheostat you eliminate the dash lights. The glove-box, map light, dome light, clock, washer button, hazards, etc are all on a different fuse. Edited July 25, 2012 by bjhines Quote Link to comment Share on other sites More sharing options...
beermanpete Posted July 25, 2012 Share Posted July 25, 2012 Another stupid question. I see some test light probes that are sharp enough to poke thru the insulation into the wire. What's the party line on that? Is it ok to poke thru the insulation, or do you guys always go to the end of a wire segment at a connector to check for voltage/continuity? I'm betting it is gonna be a connection, I'll find it or be damned! Yep, checked bulbs. Hazards work. I prefer not to push the probe through the insulation if I can avoid it. Mostly because I got tired of poking the thing into my fingers. The hole from the probe should be small enough that it won't cause a problem. Quote Link to comment Share on other sites More sharing options...
afbrian13 Posted July 27, 2012 Share Posted July 27, 2012 I would vote against probing the insulation. There are enough places to break the system open you shouldn't need to do that. One nice thing about the design of the datsun wire plugs is that you can get a meter in the back side of pins in each plug. Be careful taking a car to an "electrical guy". As an aircraft electrician I can assure you most don't have a clue what they are doing any more than you do. Plus-I bet you know your Z better than everybody else local to you, at least thats what I have found. Grab a wiring diagram and get started-Have fun! Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted July 27, 2012 Author Share Posted July 27, 2012 12 years in uniform and 4 in the Airborne, my neck and back are smoked. I hate getting under my dash. If I can't get it solved this weekend, I am going to a reputable (but expensive) wire chaser in town. Thanks everybody. You can all stand down until I report back on this weekends work. Quote Link to comment Share on other sites More sharing options...
HowlerMonkey Posted July 28, 2012 Share Posted July 28, 2012 I mentioned the radio because many installers will simply snip the green/white wire that supplies radio illumination. These often short to ground. Your symptoms don't fully support this but, if you have exhausted everything else, might want to take a look. Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted July 30, 2012 Author Share Posted July 30, 2012 (edited) Found the fault: a melted fuse holder. See pictures. The first fuse box I had in the car (when I bought it 20 years ago) melted on one of the tail light fuse posts. So, I found a newer one and sent it to somebody 15-20 years ago for an "upgrade." Well, that external fuse holder melted. Somehow over the years, I had placed a standard fuse in the fuse block-that is why it showed volts on each end, but in fact, the green/white wire was no longer even attached to it! The green/white wire was attached to the melted externalized fuse-I was totally overlooking the externalized fuse in my wire chasing. I replaced the melted fuse holder today. After that, it was just a matter of putting the electrical system together. The gauges are still pretty dim, but the new rheostat is smooth; all the lights work. So, why did the wire get hot enough to melt a fuse holder? Maybe the burned contact in the combination switch? Maybe the marginal rheostat? There is a questionable ground on the left rear side-marker light according to my ohm meter, but the light still works - could that cause it? During re-assembly, I noted that my rheostat post has a little warmth to it... And, what' up with the dim instrument lighting? Any last suggestions before I get back to the dragstrip? Edit: the missing fuse is for my missing windshield wiper motor. Edited July 30, 2012 by RebekahsZ Quote Link to comment Share on other sites More sharing options...
bjhines Posted July 30, 2012 Share Posted July 30, 2012 (edited) The hot fuse is common and related to the assembly of the fuse panel. The rivets can loosen, causing a poor connection, which gets very hot. I cleaned and soldered the entire panel, after tightening the rivets. Edited July 30, 2012 by bjhines Quote Link to comment Share on other sites More sharing options...
Pharaohabq Posted July 30, 2012 Share Posted July 30, 2012 (edited) Good job BJ. Yeah poor connection or corrosion is really the main cause of heat in the circuits. The original soldering job for 40 years ago was maybe marginal so it's not suprising we have fuse box issues. For the 240Z MM makes a replacement fusebox complete with plugs. The pointy leads on your meter is not for poking through insulation if you can avoid it, it's much more for poking into the back of plugs to reach the spades. poking into wires is an easy way to bleed, or cause a short, hopefully not both. RebekahsZ, That "add in Fuse" isn't in parrallel with the stock fuse is it? If it is, the current would be divided between the two and neither would blow before the harness melted. you should remove any fuse from the stock location and bend the holder to prevent anything from being placed there. That could explain why it was partially melted, though it's likely the connector is corroded. Edited July 30, 2012 by Pharaohabq Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted July 30, 2012 Author Share Posted July 30, 2012 No not in parallel, just sitting there as an easy opportunity for a short. Took the fuse out of it; should be OK now. All good now, lets let this thread fizzle out into the archives. Quote Link to comment Share on other sites More sharing options...
benhurley5 Posted July 22, 2014 Share Posted July 22, 2014 Was a stereo recently installed? @HowlerMonkey I recently installed a stereo and am suddenly experiencing this problem directly following the install. Do you have an idea of what it might be? Quote Link to comment Share on other sites More sharing options...
Baki 280z 2+2 Posted October 26, 2015 Share Posted October 26, 2015 I had a same thing happend and i relized that all of my bulbs were burned outso i replaced them and all in working condition, exepct dash light , i will have to get to it and replace that one too Quote Link to comment Share on other sites More sharing options...
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