Speedymaru Posted April 14, 2018 Report Share Posted April 14, 2018 So I was going to drive my 1978 620 into town to get gas tonight, and I went to start my truck and it wouldn’t crank. I tried to headlights to see if I had battery power, and they didn’t come on. I disconnected the positive lead from my battery for a while, then reconnected it. My truck then was able to crank, but my headlights won’t come on. I already checked the fuses in the cab, and they’re all good. I also removed the headlamp fuse and put it back in to see if the contacts were dirty, but it didn’t help. The PO rewired part of the headlight circuit. There is a pullout switch to turn them on and off, and a click button type switch by my feet for the brights. I can add pictures if that doesn’t make sense. I’m not really sure where to begin diagnosing. Any info is appreciated Quote Link to comment
Dolomite Posted April 14, 2018 Report Share Posted April 14, 2018 I’d start by thoroughly cleaning cables and posts. 1 Quote Link to comment
datzenmike Posted April 14, 2018 Report Share Posted April 14, 2018 This. Clean and tighten BOTH cables and battery posts. If stripped bolts, replace. Practically impossible to troubleshoot lights that have been messed with. There's just no telling what some incompetent, though well meaning idiot may have done to it. Quote Link to comment
wayno Posted April 14, 2018 Report Share Posted April 14, 2018 Does the 620 have fusible links? 1 Quote Link to comment
datzenmike Posted April 14, 2018 Report Share Posted April 14, 2018 Yes, a single Green one that goes to the fuse box and the ignition. If blown, NOTHING will work. 1 Quote Link to comment
banzai510(hainz) Posted April 15, 2018 Report Share Posted April 15, 2018 make I simple ck for Power using a test light. Make sure light works by touching the 12volt on Battery then work your way up to the fuse box. . Lights should come on. Put a new fuse in as a old one may look good in the galss but the ends are broke inside If it worked before then its just a connection issue most likely. Even if a hack wire job. Last power proplem I had was a broken bolt n battery cable. I would get a 1 start then battery would look weak. I bought cables and battery when I took it apart said Fuck maybe that's all it was . Quote Link to comment
Speedymaru Posted April 16, 2018 Author Report Share Posted April 16, 2018 Put a new fuse in as a old one may look good in the galss but the ends are broke inside If it worked before then its just a connection issue most likely. Even if a hack wire job. I just took the switch out and This is the problem. The fuse that’s on the switch itself looks good, but is actually broken. I’m heading in to grab a new one and will check back when done! Thank you all 1 Quote Link to comment
Speedymaru Posted April 16, 2018 Author Report Share Posted April 16, 2018 Replaced the switch and put it all back together and they’re working again! Thanks again 1 Quote Link to comment
BestyBlue77 Posted April 18, 2018 Report Share Posted April 18, 2018 The simplest solution is usually the right answer. And more heads are better than one! Go Team Ratsun!! Quote Link to comment
datzenmike Posted April 19, 2018 Report Share Posted April 19, 2018 I just took the switch out and This is the problem. The fuse that’s on the switch itself looks good, but is actually broken. I’m heading in to grab a new one and will check back when done! Thank you all Can't be a Datsun switch. Hard to trouble shoot home made fixes. Like a doorbell switch on the steering column for the horn. Or a light switch on the dash for the headlights Quote Link to comment
Speedymaru Posted April 29, 2018 Author Report Share Posted April 29, 2018 Yes, it is not a Datsun switch. The previous owner wired something up just before i bought it. Thank you all for the help Quote Link to comment
don51o Posted July 7, 2018 Report Share Posted July 7, 2018 rewire properly if you put in "big" lights Quote Link to comment
Z-train Posted October 2, 2018 Report Share Posted October 2, 2018 Sorta related.......when I hit the high beams , all head lights go out. Gotta be the highbeam switch....right? Quote Link to comment
banzai510(hainz) Posted October 4, 2018 Report Share Posted October 4, 2018 when all lights go out when switched to high beams its the relay. clean contacks or get a new one. later 510s had a relay with the wires on it the other just a plug in relay 1 Quote Link to comment
Speedymaru Posted October 6, 2018 Author Report Share Posted October 6, 2018 I’m having more problems with my headlights again. The headlight switch gets very hot when the lights are on. I haven’t been using them because I don’t want to start a fire. I’ve been trying to figure it out myself before asking for help, but I haven’t been able to fix it. I’ve checked the switch connections for clean contacts and they’re all good, I’ve removed the electrical “plugs” from the back of the fuse box to make sure they’re clean, I’ve checked around for high resistance, I just can’t figure it out. Any ideas? This is not stock wiring by the way. I can try to get pictures of the wiring if that would help. Thanks in advance Quote Link to comment
datzenmike Posted October 6, 2018 Report Share Posted October 6, 2018 On 4/28/2018 at 6:47 PM, Speedymaru said: Yes, it is not a Datsun switch. The previous owner wired something up just before i bought it. Thank you all for the help Who knows what this switch is rated for? 55 watt dual low beams draw about 9 amps. A house light switch and 60 watt bulb is 0.5 amps. Quote Link to comment
Speedymaru Posted October 6, 2018 Author Report Share Posted October 6, 2018 I know that my headlights have worked correctly for about 6 months. What would you recommend I do? I’m not good with electrical stuff so forgive me for the stupid questions Quote Link to comment
datzenmike Posted October 6, 2018 Report Share Posted October 6, 2018 They are not stupid questions. Unfortunately there is no easy answer. A previous owner butchered the wiring and probably added several problems on the way. You are in the PNW alive with old Datsuns. Try to find another wiring harness? Quote Link to comment
Speedymaru Posted October 22, 2018 Author Report Share Posted October 22, 2018 Sorry for the late reply, been pretty busy. That would be the correct thing to do, but I’m afraid it might be out of my expertise. I would like to try to locate the source of the problem. They’ve worked before so I’m thinking they’ll work again. I may end up taking it to a shop to have them take a look. I’m not well versed in wiring. Thanks for the help Quote Link to comment
banzai510(hainz) Posted October 22, 2018 Report Share Posted October 22, 2018 (edited) clean connections. a shop might just rig it up to work . I would buy a h4 harness. I would get it to work and just use the old light system to trigger the H4 harness so you wounldnt draw alot of current on the stock light circut. the H4 harness would then be powered by a relay from the battery. somebody near by could maybe help you. key is get it back to stock then add the harness key is knowing what the previos owner did first Edited October 22, 2018 by banzai510(hainz) update Quote Link to comment
Speedymaru Posted October 22, 2018 Author Report Share Posted October 22, 2018 Okay. Would I use different headlights with the h4 harness? And just to verify, you’re saying to use the wiring I have now to trigger a relay to supply power to the h4 harness? Quote Link to comment
banzai510(hainz) Posted October 22, 2018 Report Share Posted October 22, 2018 Read up on it. you unplug your pass side outside lamp,it has a 3 prong plug. this 3 prong will now be your trigger input to a new H4 harness . The new harness has 2 relays one for the lows and 1 for HIGHS of the outer lamps. and Power. Your stock lamps and H4 lamps have 2 elements on there. the Inner HIGH lamps will not be touched and hopefully will still work. there H4 harness are about 25 -40$ for the cheaper Chinese better ones run upward. I got mine from a place called 4 crawlers or soemthing like that show installed on a Toyota 4x4 pickup Just remember Im trouble shooting from afar. so hard to tell what you have. but Im postive your fuses in fuse box will not melt anymore Quote Link to comment
Speedymaru Posted October 24, 2018 Author Report Share Posted October 24, 2018 Awesome, thank you very much Quote Link to comment
Speedymaru Posted November 1, 2018 Author Report Share Posted November 1, 2018 Hey, I have another question. Pretty much all the h4 kits I’ve seen only have 2 terminals. Does that mean I mean I need to buy two of the kits to supply power to all 4 lights? Quote Link to comment
Speedymaru Posted November 1, 2018 Author Report Share Posted November 1, 2018 Never mind, I found a 4 headlight version. I might still buy 2 separate harnesses because of the way the headlights are wired currently. I think it should work out. Thank you all for the help Quote Link to comment
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