BLKMGK Posted October 5, 2001 Share Posted October 5, 2001 Okay, feeling too sick to work on carb I decided to check out 2 electrical issues. 1) Passenger side turn signal not working in the back. Bulb is good. I check voltage on the contact - nothing there. I check it on the other side's socket and see a pulsing voltage. I pull the harness for that lamp set and check it at the socket - I see pulsing voltage. I plug in a harness from another lamp set - nothing. I plug in my lamp set and try to check voltage on the backside of the pin going into the socket - no voltage?! Is it possible the blinker module up front is bad and can't drive the bulb back there? The front blinks fine though. I'm open to suggestions, my next step will be plugging in the other lamp harness again and checking for volts on the back of the pin but I'm not expecting anything. It used to work fine... 2) When the motor is running the high beams pop on and won't go off?! I thought maybe it was the little relay setup I'm using to turn on an LED for high beam indication but I'm not so sure. When I first crnak up the car with the lights on I see the high beams pop on but th eLED is dark. Kick on the high beams with the stalk and it lights. Kick them off and the LED stays lit as do the beams. These are Hella H4s so I'd really like to fix this - I'm blinding people. I didn't get a chance to check input voltage to the relay up front (not stock) but will do that next. I'm actually wondering if engine vibration could be jiggling the relay closed? I may also try disconnecting the LED setup inside the car. The only place that it could get phantom voltage that I can think of when running like that would be the fuel pump's oil pressure switch but I cannot imagine how that would occur. I'd appreciate any ideas - this one has had me stumped for about a week but I hadn'y really looked at it much until tonight. Hrm, just realized I've not tried turning OFF the car to see if the lights dim after it shuts down (smack). Bizarre! Quote Link to comment Share on other sites More sharing options...
383 240z Posted October 5, 2001 Share Posted October 5, 2001 Did you change your harness to the painless or is it oe? If oe you might have voltage but your amps might not be able to push through 20 some years of copper rot. My 70 Jaguar E-Type used to do this to me on a regular basis DAMNED LUCAS!!!Keith Quote Link to comment Share on other sites More sharing options...
383 240z Posted October 5, 2001 Share Posted October 5, 2001 Did you change your harness to the painless or is it oe? If oe you might have voltage but your amps might not be able to push through 20 some years of copper rot. My 70 Jaguar E-Type used to do this to me on a regular basis DAMNED LUCAS!!!Keith Quote Link to comment Share on other sites More sharing options...
Tim240z Posted October 5, 2001 Share Posted October 5, 2001 Had the same problem with my 73's rear left marker lamp, ended up being a bad earth on that light. Tim Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted October 5, 2001 Author Share Posted October 5, 2001 When I check the power at the lamp I'm grounding to the frame - weird that it's like the power isn't going through the socket.. Harness is OE and I measure voltage at the harness just before it goes into the last bit of harness attached to the lamps. That little piece is socketed on the 240. I also trimmed away a bit of insulation on the suspect wire near the socket and got no juice - that's when I decided to check behind the socket going to the main harness. What a PITA! Quote Link to comment Share on other sites More sharing options...
pparaska Posted October 5, 2001 Share Posted October 5, 2001 Turn Signal Lights. Sounds like it's in that last bit of harness between the connector and the bulb socket. But the turn signal switches on the Z are notorious for this kind of stuff. See my site for my relay mod. Can you plug the other short harness/tail light into the side that's not working to try to isolate it that way? High beam: try unhooking that relay for the highbeam indicator you put it. My money is on a sneak circuit there. Good luck! Aren't electrical gremlins fun? Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted October 7, 2001 Author Share Posted October 7, 2001 Okay, this just sux... Worked on the headlight "issue" tonight. Here's where I'm at: With engine off I turn on lights - tap relay area and high beams come on! Bad relay right? Unplug one relay (either one) and all lights go out. Plug it back in and lights are on, tap brings on high beams. I measure voltage at one relay and it's 5volts at one point, 11+ when I hit th estalk. Looks like some voltage MIGHT be sneaking in making that relay trigger more easily? Only thing recently changed was my circuit for the high beam indicator. For that circuit I took the two wires going to the high beam bulb and ran them to a relay. I pull those and leave them unhooked. While goofing around under there I've now got it so that ONLY the high beams work Looking at the stalk switch it switches GROUND and seems to work fine. Gave up at this point. Question - what happens when a Z's high beam indicator bulb goes out? If I short those wires together I blow a fuse I'm thinking of putting a bulb on to see what happens - need to measure voltage with stalk in both positions too. I will also be checking the voltages at the "old" headlight connector. This will allow me to isolate out the relay harness as causing the problem. Will be looking at the schematics tonight too I think. Didn't go out tonight on account of the flakey headlights - not cool at night (ahem). No work done on rear signal tonight - tomorrow maybe. Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted October 7, 2001 Author Share Posted October 7, 2001 Aww great. I checked voltage going out to the headlights. One way I see 10volts on one wire just fine. Click it again and I see 5volts on ground, 5volts on the lead that had no power before. Tapping the relays kicks on "high". Need to double check this as it's pretty confusing. On what I assume is "highbeam" I get 10volts on the highbeam indicator, click it again and I get 5volts?! Think I need to put something in this circuit. I think when it's got 5volts on two wires is when tapping on the relays clicks on highbeams. Kripes this is weird! Pretty sure it's not coming from the switch area. If I disconnect the stalk and use a wire to ground pins I see the same behavior I'm pretty sure. Going to have to take notes to keep track of this - what a PITA! Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted October 7, 2001 Author Share Posted October 7, 2001 3pages of notes - pulling my hair out here. Question - the stalk appears to switch ground in order to change from hi to low beams - this sound right? At the bulb - is there a common HOT and then switched grounds to lite the bulb?! Would appreciate a sanity check here. If it's NOT a common hot then I'd appreciate someone explaining to me how it works? I can take the connector from the stalk and ground pins in order to lite the lights. Low comes on but so does high always. I'm seeing a hot up front nearly always which I thought was the high beams but now I'm not so sure. Pulled ALL fuses except for the circuit that goes to the bulb I'm using - no change in behaviour. I've inspected the harness as best I can - no damage visible. Am going to examine the headlight stalk switch a bit I think. Having a heck of a time understand how this circuit is supposed to work... Wiring diagrom from Nissan is spaghetti and damned confusing. Anyone got a diagram of just the headlight circuit? Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted October 7, 2001 Author Share Posted October 7, 2001 Figured out the headlight problem When I wired the headlights with my "Painless" wiring relay setup I was VERY careful to wire it up so that the pins in the plugs matched. I had to cut the plugs off though since the plug wouldn't fit into the headlight housing. I even wrote down wire colors to get it right! However I was seeing some things that didn't make sense - primarily the fact that if I removed either relay all lights seemd to die - I expected one relay for high and one for low... Completely frustrated and unsure of how this circuit was supposed to work I decided to look at the driver's side circuit. Gee, it functioned as I expected - one wire stayed hot while the other two alternated to ground withthe stalk up front. Hrm! Looking at the wires I hooked up months ago I noted that the one that was COMMON to both relays wasn't hooked to the wire that was hot all of the time. Hrm!! I looked closely at the relays and saw nowhere that that wire was tied to ground so... I tied the wire that was always hot to it. Gee, lights now work "correctly". Rather than the common wire being a ground in this case it's a HOT wire - cute that it's BLACK on the "Painless" harness. I'm not sure what to think. Are most cars switched HOT and not ground? I was pretty careful wiring this thing. I could swear it worked fine but I didn't drive it much. Motor off with no vibration it DID work but obviously not putting the voltages in the right places .. Well, I think it's fixed now (sigh). On to the tailights! Quote Link to comment Share on other sites More sharing options...
Mike kZ Posted October 8, 2001 Share Posted October 8, 2001 Does this change anything in your Headlight Relay article? Quote Link to comment Share on other sites More sharing options...
scottyMIz Posted October 8, 2001 Share Posted October 8, 2001 Hey blk i had the same prob on my 76 but it was the hazard switch it was dirty and the contacts wheren't getting good connection.Alli did was switch it back and forth a few times and it wroked.It will also test to see if your wires are good to the back. Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted October 8, 2001 Author Share Posted October 8, 2001 Hrm, does this change anything in the article? Yeah, it probably does - I need to reread it and see. The more I think about it the more irritated I get. I can remember leaving pigtails of wire on both the stock and Painless harness so that I could look at the wire colors with the two plugs together and get the wiring "right". I either screwed up stupidly or the wiring was whacky from Painless for this application. Is my article up now? I'll hunt it down and reread it Turn signal stuff... Redid my measurements of the wires back there. I DO see some voltage pulsing back there on the lamp side of the plug. Get this - that sucker switches ground too! I put my meter on tone, touched it to ground, and I can hear the blinker alternating ground! Weirder yet, if I hit the hazards the light BLINKS At this point I think it's the flasher module. This sucker WORKED fine forever and now it suddenly stops? Methinks that the blinker module is th emost likely culprit and I'll check it out when I get a chance to hit PepBoys etc. What a PITA but at least I'm not blinding anyone. My secondaries MAY be opening now too. Hard to tell but the little clip moved a bit and I think I might have felt them tipping in. Nose really rises when I hit the gas in 2nd May dyno it again and see when I'm more sure, possibly put a camera over the carb and film it to be sure Quote Link to comment Share on other sites More sharing options...
Mike kZ Posted October 9, 2001 Share Posted October 9, 2001 Here's your article: http://www.hybridz.org/TechA/0001/Painless%20Wiring%20HC.htm Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted October 9, 2001 Author Share Posted October 9, 2001 Hrmph, note my emphasis on wiring things carefully Interesting that I thought the black wire was ground - in reality I think that's the wire that supplies a constant 12volts and is wired to the "ground" or common wire on the Painless harness. I wonder if it's possible that even after noting the wires etc. that I STILL screwed it up? If anyone is about to undertake this on a 240 I can share wire colors etc. to try and make it easier to do. The dark wire is the constan hot, the redwhite and redother color are the switched grounds. One is highbeam, the other low... Quote Link to comment Share on other sites More sharing options...
pparaska Posted October 10, 2001 Share Posted October 10, 2001 Jim, You've found out the Datsun Headlight Secret. The dude that designed it was a high school flunky, no doubt! Yes, the headlight on/off switch sends +Battery voltage to the common of each headlight (through each fuse). And the hi/low switch sends the ground to either filament. It's got to be the stupidest wiring of headlights I've ever seen. Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted October 10, 2001 Author Share Posted October 10, 2001 So, other headlights aren't done that way? Horn is the same way, so is the turn signals?! Why in the world would you build a car with a common ground and then switch GROUND to turn on so many things?! Isn't that bassackwards? Parking lights aren't that way but brake indicator is and so is the highbeam indicator (sigh). Dome lights too. The list is endless - the e-brake and dome light I think I can understand but the rest? Quote Link to comment Share on other sites More sharing options...
pparaska Posted October 10, 2001 Share Posted October 10, 2001 I can't remember the details of all the rest of the circuits, but I DID map out the entire harness of my 73. The headlight circuit was the weirdest part I remember. That and not using relays hardly anywhere they should have! Quote Link to comment Share on other sites More sharing options...
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