Da Flash

Thanks for the reply, I have wiggled the harness with no noticeable difference on the meter. My car is a '71 240z (8/71 manufacture date) and the fusebox has short pigtails.

I've been trying to track down the source of my "IGN" fuse blowing within seconds of turning the key to "ON". From my probing around with a multimeter, I've discovered that the green wire side of the fuss holder is getting continuity with ground (i.e. the dash metal frame. I've looked for a wiring schematic that has the green wire on the fuse box transitioning to a red/blue wire after the 6 wire connection but, all the diagrams that I've found don't show the wire changing colors!! From my probing around, I've discovered that this wire goes to the hazard switch but, cannot figure out where it would be coming in contact with the dash frame. I have the dash out of the car, for ease of checking things out. For what it's worth, the engine runs fine but, I don't have gauge lights, gauges or a tach. 1. does anyone have a schematic that has the green "IGN" wire changing to red/blue at the conntector?? 2. Are there any places where this wire could come in contact with the dash metal frame?? This electrical stuff come be a major PITA!!

OK, I can see from the colored diagram what you're saying, it makes sense! Now the question is where in the hell does that blue wire go??? The one that's crimped to all of the red/blue wires including the one that goes to the rheostat. The crimp point looks factory (after digging through a lot of electrical tape!)but, I don't see anything blue (with no line) in that area on the diagram.

OK, I had to give it a break and deal with that whole "work, family, non-car-related" stuff. I think that I narrowed it down to a bad gauge bulb that was causing a short to ground. While I love my 240, who came up with the 1-wire/ground to the gauge body concept??? In one of earlier post, I noticed that when I hooked up the batt neg cable that 2-3 dash lights would come on without using the light switch. So during my investigation, I noticed that the PO had spliced into the big W/R that goes from the fusebox to the engine compartment, this appears to be where some of the dash bulbs were getting power from. The bad connection/bulb was/is causing the power from the big W/R wire to jump to ground and blowing the fuse and melting the plastic connector in the W/R wire. It's been like that as long as I've has the car but, this is the 1st time that I can recall it blowing fuses!! I've included 3 shots of the hack job that the PO perform. For clarification, the pic of the yellow wire coming off of the W/R wire is where it was spliced into. the pic of the circled Y wire and L wire with the alligator clip is the connection and lastly, the pic of the L wire and the 3 R/L wire (that go to the bulbs is where the L wire terminates). I've confirmed that with the L wire cut, that the fuse won't blow and no more positive to negative continuity anymore. Since I know that the L wire should get power from somewhere like a switch or the like, where should the L wire get it's power for the dash bulbs???

Well, I haven't been able to start the engine in a few days, I think that the issue with the ignition circuit is preventing it from starting. I have been poking around at a few connections to learn some things and see what I can find. I think that I've actually narrowed it down some. While checking some connections with my multimeter set for resistance/Ohms, I noticed that If I check the "E" or the "A" ( hell "F" + "N" too! )on altenator to body ground ( yes I was smart enough to disconnect the ground cable from the battery ) I had a closed circuit, i.e. the meter read ~002!! It did the same thing if I check resistance between the (+) battery cable and ground so after following the advice that you gave me earlier, I pulled the connectors, one at a time, in the pass footwell one at a time until I found that if I unplug the single "big white wire with no stripes", that my short between pos and gnd disappears. I isolated it to the dash side of the harness. The big white wire goes to the pos side of the ammeter, "A" on the voltage reg, the fusible link at the starter and, a 10 amp fuse at the fusebox ( not sure which one but, it's not the IGN fuse ). I disconnected the BWW from the ammeter and noticed that if I check the (+ post) to the (- post. ) on the back of the meter that there is still a short to ground. Hopefully this isn't too long of an explanation. Thanks for your time!!

Ok, I finally got some time to work on the Z. I got the alt tested and it was bad, so I got a new (externally regulated ) one and still have the light turning on so, I borrowed a known good VR from a buddy and the damned light still comes one. What esle can you think of tat might have been affected by using the wrong altenator??

Thanks for the pearls of wisdom! When I pull the T-plug on the altenator with the VR plugged in, the light stays off. Looks like it's time to get the alt tested. I think that it might be a 280 alt with an internal VR. Strange thing is that it's been running fine for ~18 months!! One of the many lessons learned in the latest episode of "Me and this damned Z" is, if you're blowing the "IGN" fuse, check the ignition circuit instead of what stopped working (i.e. the harness going to the tach, gauges, etc.) first!!

Thanks for the clarification!!! I disconnected the voltage regulator and the bulb went out (Yay!!!) and yes I had the bulb hooked up outside (ground )of the bulb to the left side of the fuse holder and contact point on the bottom of the bulb (positive) to the right side of the fuse holder. I suppose that this means that the VR is bad??(Damn, I just got a new one ~ 18 months ago from MSA!!) I'll have to look in the FSM to see if there is a way to test it for sure. For what it's worth, when I pull either of the 2 wires on the + side of the coil, the light stays on. Also I have a 280zx distributor so, I don't have points Wouldn't you know that with my "Schleprock" type of luck, now when I hook up the battery, I get dash lights even though the light switch isn't even connected!! I truly loathe electrical!!! Thanks for pointing me in the right direction!!!

I have been trying this technique ( the light bulb instead of the fuse ) for a couple of days on and off and I always get a bright light. If I'm understanding this correctly, the IGN circuit sees 12vdc as soon as you turn the key to On/Start, so wouldn't it light the bulb with or without a short/bad connection?? Since I have the dash pulled back a bit, I have disconnected the gauges and anything else in the circuit but I still get the light as soon as I apply 12vdc to the circuit.

Now you tell me!! (J/K!) At first I was hesitant about pulling the dash but, after seeing what the PO did, I would've been hard pressed to find ALL of the hacks that were perform! Between a really cheap alarm that I didn't even know was there, where he decided to tap into a "hot" wire for the non-existent radio and, the crimped wires for the antennae up and down switch (who uses the up and down switch??), I had some patching to do. I still haven't found the corroded connection or hot wire grounding in the IGN circuit!! Hopefully cleaning all the connections under and behind the dash does some good!!

On my harness, it changes at the fusebox connector right under the radio. The green wire is only ~6 inches long, it looks a lot longer on the diagram!!!

This is just so much fun!! I ended up pulling the dash to get to those damned wingnuts that hold the tach in (who uses wingnuts under a dash!?!) I also had to clean up some questionable wiring that the PO hacked in. One question; the green wire that comes out of the fusebox (off of the IGN fuse) changes to a RL (red withe blue stripe) but in the fsm diagram, it still shows it as green, does anyone know if this is correct??

I am trying to hunt down a short in my ign system that's causing 20A fuses to blow as soon as I turn my ignition to the on or start position. I have tried using my multimeter but, apparently I'm not quite as good as I thought. I get a reading of 001 if I measure resistance between the B/W wire from the ign switch and the fusebox so that looks like it should but if I check between the B/W wire at the switch and ground I get 1485!! I also get the same reading if I check the opposite side of the fuse, the green wire. This leads me to a short to ground on the green wire side of the fusebox. Is this correct? It looks like the green wire goes to the tach, speedo meter and a few other thing, any suggestions on how to narrow it down?? '71 240z 5-speed. TIA!!

I got the harness installed and cleaned up the contacts in the switch. That did the trick!! While installing the harness I noticed that the driver side connector had a lot of green oxidation on the terminals (probably why there was the extra draw on my light circuit.) so I cleaned all that up and also swapped the fuses to 5amps. I must say that the light are definitely brighter!!

Cool! For some smart reason, I knew that you'd know what to do!! I'll get on it and let you know how it came out. Thanks!

Hey Dave, I check the White/red wire on top of the switch it has 12.4dcv, when I turn the switch on lo and behold I get 0.2dcv on the red wire on top of the switch!! So I guess that it is the switch:mad::mad: Yes I have your upgraded harness BUT, I haven't put it in yet (figured I'd wait until the winter to put it in with some other stuff!). To remedy the problem could I just clean the contacts in the switch and then install the harness?? Thanks for the quick reply!! Oh yeah, you should drop the "wanna be" at the end of your title, you're the real deal!!

Yesterday on the way home I noticed that my headlights weren't working, all the others i.e. sidemarkers, brakes, turn signals, etc. seem to be fine. My first thought was the combo switch but, I had it rebuilt by "Zs-ondabrain" (top notch if I say so myself!!) along with the turn signal switch back in June. So I moved on to the fuses, all were good. I've tried to see if there was ~12dcv at the lights themselves but couldn't get anything. Lastly I checked for 12dcv at the fuses in the fuse box. I got 11.8 dcv on all of the other light fuses but nada at the 2 headlight fuses!! So obviously the problem is getting power to the fuses/lights but, if this isn't the switch (which I highly doubt, they still look brand new [once again, Thanks Zs-ondabrain!]) what else could it be?? On a side note, not sure just how relevant this is but, I had noticed that my dash voltmeter has been bouncing +-+-+-+- from time to time for a few days before I lost my lights, I chalked it up to a slightly loose alternator belt which I tightened but, it still didn't stop the needle from bouncing from time to time. Before the lights gave out on me they would dim/brighten with the bouncing. '71 240z TIA

I almost don't have the word to describe what Dave's rebuilding skills and harnesses have done for my 240z!!! I had to look really close to make sure that these were indeed my switches instead of BRAND NEW! Out of the few things that now work, I love the "hit the turn signal once (without having to hold it) and it works! The difference in my lighting now and before are night and day, if you can spare the loot you won't regret it!

When I check continuity between the sending unit body and the frame, it's good ( 0.3 ohms). When I check continuity between the tank and the frame, same thing but, when I check the ground wire going to the sending unit and the ground wire going to the gauge, I get a resistance of ~45 ohms!! I'll double check the gauge connectors and let you guys know!!

Well I can't switch the connectors because I did a connector mode a few years ago, I basically eliminated the bayonet ends and soldered on a wire with a male spade end on one wire and a female on the other. Tried as I may, I couldn't find new bayonet fittings! I've ohmed the sending unit and a new one ( I hate buying new stuff that doesn't fix the problem!!) they both measure the same resistance give or take. On my 71 it's about 11-80 ohms. I'll checkout the connections at the gauge to see if that helps. Do you guys think that it could be a grounding problem?? The reason that I ask is that all seems fine until I put on the retaining ring.

I've had that problem before, It ended up being the fusebox one time and a "broken but looked fine" fuse just recently. checkout the fuses first and if they turn out to be OK, then look to see if you have melted plastic around the lights fuses. Hope this helps!!

I recently cleaned out the tank in my '71 and installed the tank, sending unit and O-ring. Now the gauge is pegged at full even though I know I only have ~1 gallon in there!! While removing and checking the sending unit, I discovered that it would read fine as long as the retaining ring wasn't on but, as soon as I the ring comes in contact with the unit and tank, the gauge goes off. The ring looked a little rusty and it wouldn't ohm when I used my multimeter so I cleaned it up with some emery. Still the same result!! From my very limited electrical background, I've figured out that this has something to do with grounding. Has anyone else run into this problem, and if so what did you do to remedy it?? Any and all suggestions are appreciated!!

If you have bled the clutch, you have good pedal pressure and, you're not losing fluid, then I'd say that you might have the wrong size push rod that goes between the clutch slave cylinder and the fork that pushes in the release bearing. When I got some parts mixed up with my 5speed swap, I couldn't put the car in gear either until I put in a slightly shorter rod then all was well (I know if I had dropped the tranny and put the correct sized collar on I could have accomplished the same thing!) As far as the 1 bright 1 dim headlights, for me it was replacing the fuse box that did the trick. The best tell tale sign that it's the fusebox is melted/wavy plastic around the fuse holders! Good luck!!

I've been hunting down the cause of an intermittent "no crank" issue that appears to caused by a shaky fusible link to harness connection. The white plastic connector on the harness is brittle and 60-70% gone!! I can cobble it back together with dielectric grease and eletrical tape but, I would rather replace the brittle connector with a new one (if that's even doable!) I thought about havesting one from a junkyard 240 but, it would be ~37 years old too! Any suggestions on how to make this connection water/corrosion proof again??

Now now guys, I'm a windows kinda guy! As far as the "no spark" situation goes, it ended up being something in the distributor. I switched to another one and she fired right up!! I had the dizzy lying around, I got it from napa and never thought it worked as well as my ZX boneyard find. The napa dizzy came with a off brand module (it doesn't have any nissan/12-80 on it and the cover is made of cardboard that can be pryed back to see the inner working) plus the model# is somewhat different than the ZX dizzy. I'll have to post some pics Thank you everyone for your help, if anyone runs into these problems, Blue's page helped out a bunch!!