logan1 Posted October 5, 2011 Share Posted October 5, 2011 (edited) I been stuck for the last 2 day on a wiring problem that I just can’t figure out. On my 1970 240z all my fuses are stable and I have everything on the wiring harness connected per the FSM but my headlights and tail lights/brake lights are not getting any power. However my backup/reverse lights are getting power. I just converted my headlight with a HID kit and my taillights are an LED kit. If i run wire from the positive of the battery directly to the back of the taillight the light-up just fine. So i obviously have an open circuit somewhere but can figure out where the harness is open. To give a little background on my car; the car has been through a full frame off restoration over the last 2.2 years and I am finally close to being able to drive it. The car starts and runs like a champ; it has the E12-80 upgrade with the 280z tach. I reinstalled the dash and wired everything up but am unable to get power to the headlights and taillights. I’m sure it’s something really simple that I’m missing but at this point I’m unable to figure it out on my own and need some input from you guys. Any help you guys can offer is appreciated. Edited October 5, 2011 by logan1 Quote Link to comment Share on other sites More sharing options...
beermanpete Posted October 5, 2011 Share Posted October 5, 2011 Check the combination switch and the grounds near the steering column. The headlights are controlled by the ground to select the high and low beams. Quote Link to comment Share on other sites More sharing options...
logan1 Posted October 6, 2011 Author Share Posted October 6, 2011 OK i got the tail lights working. 1 of the connectors in a 6 prong plug was lose and was causing the problem. I still cant get my headlight and brake lights to work but at least i got the running lights on for now. Quote Link to comment Share on other sites More sharing options...
rsicard Posted October 6, 2011 Share Posted October 6, 2011 The headlight circuit on the 240Z has high current going through the headlight combination switch/stalk on the steering column. With age and usage the contacts in the switch get really dirty from all the power being drawn through them. This is really a design problem. Adding HID headlights just makes the problem WORSE for the switch. Need to add headlight relays that are controlled by the combination switch such that a small current through the switch controls a high current through the properly rated relay for the headlights. Putting LEDs on the other lights is the proper way to go as they reduce the amount of current and power through the steering column stalk switches. Quiet likely these switches need to be gone through and cleaned up and then the headlight relays installed. There is a kit for the headlight relays available. First best remove both headlights and check for power at the three prong connector with the headlight switch on. If +12 volts is present there then the fuses and wiring to that point is OK. There is a 12 volt return (ground) wire back to the headlight switch. This can be found by doing a continuity check from the headlight three prong connector back to the headlight switch connector on the steering column. If those connections are OK then applying a ground to those pins should light each headlight as each has a separate fuse for left and right headlights. Go to classiczcars.com and find the gentleman that rebuilds the combination switches and send yours to him for rebuild. He does a good job and can also help you with your electrical system. Quote Link to comment Share on other sites More sharing options...
clutchdust Posted October 6, 2011 Share Posted October 6, 2011 I second the vote for the headlight/combination switch. I didn't have any problems out of my headlights but it took quite a bit for me to get my tail lights working. Had to pull the turn signal switch apart several times before I finally got it figured out. The trickiest part to fixing this particular switch is the brake light interrupter contacts. If they don't break contact as the turn signals make, it can overheat the terminal and will melt the solder joint on the wire terminal. If you try to repair it yourself, just remember to never use an aggressive material to clean the contact surfaces. 1000 grit sandpaper at the most, but generally I like to use something like steel wool or even a scotch-brite pad. The contacts have a silver coating on them and if you remove that coating, it will create nothing but problems later on. Quote Link to comment Share on other sites More sharing options...
Tony D Posted October 6, 2011 Share Posted October 6, 2011 (edited) Did you do the wiring before or after the body was put back on the frame? I've seen it where wiring was inadvertently pinched or cut in the process of putting the body-on-frame and that can cause all sorts of weird ghosts. (Usually in a place where you can't see it!!!) Never seen it on a 240Z though. Edited October 6, 2011 by Tony D Quote Link to comment Share on other sites More sharing options...
72 SBC 240Z Posted October 6, 2011 Share Posted October 6, 2011 (edited) ^^ because unibody Edited October 6, 2011 by 72 SBC 240Z Quote Link to comment Share on other sites More sharing options...
Tony D Posted October 6, 2011 Share Posted October 6, 2011 Uh... think about it for a second more 72 SBC 240Z.... think about it... Quote Link to comment Share on other sites More sharing options...
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