rsdaumer Posted January 16, 2012 Report Share Posted January 16, 2012 Hey everyone. Almost got the brakes cleaned up, adjusted and bled, so next big problem is the headlight relays. the PO did some crazy wiring to show me the headlights worked by bypassing the relay. there were two metal relays in the engine compartment on either side of the fan shroud. those were bypassed and the lights kinda come on but not really. i ordered a new relay from rock auto, its plastic with 5 posts (the other two had one with 4 posts and one with 3 posts) could anyone post a pic of a 74 engine bay with the relay hooked up correctly? trying to get this truck drivable ASAP. thanks everyone! Russ Quote Link to comment
Eagle_Adam Posted January 16, 2012 Report Share Posted January 16, 2012 here ya go Drivers side: Passenger Side: Quote Link to comment
rsdaumer Posted January 16, 2012 Author Report Share Posted January 16, 2012 ok thanks! any idea where i can get these two relays? i ordered one from rock auto and its plastic with 5 prongs. two say COIL, one says NC, one says NO and the other is COM Quote Link to comment
Eagle_Adam Posted January 16, 2012 Report Share Posted January 16, 2012 call nissan??? not sure on where to get em - ill look for parts #'s next time i go out to the truck Quote Link to comment
rsdaumer Posted January 17, 2012 Author Report Share Posted January 17, 2012 yeah besides a japanese symbol, mine have no writing on them at all Quote Link to comment
MikeRL411 Posted January 17, 2012 Report Share Posted January 17, 2012 ok thanks! any idea where i can get these two relays? i ordered one from rock auto and its plastic with 5 prongs. two say COIL, one says NC, one says NO and the other is COM COIL - Self evident, that's where it connects to. NC - Normally closed. NO - Normally open. COM - Common. Depends on your vehicle, "Common" may mean ground or +12 volts depending on whether you have switched voltage or switched ground scheme. 1 Quote Link to comment
Eagle_Adam Posted January 17, 2012 Report Share Posted January 17, 2012 couldn't find a part # sorry Quote Link to comment
rsdaumer Posted February 27, 2012 Author Report Share Posted February 27, 2012 hey everyone. finally got the brakes good on the truck so im trying to tackle this headlight issue so i can start driving it. called nissan with the original part number, no relays are available anywhere in the country. would anyone happen to have an extra one somewhere? had three different people look at the new relay and try to get it to work; no one could. thanks! Quote Link to comment
banzai510(hainz) Posted February 27, 2012 Report Share Posted February 27, 2012 the 3 wire relay is usually a horn relay. these are ez to open up and ck and clean. usually burnt up contacks that can be cleaned. the new rockauto realy will work if you know how to wire it in. post where you live .Lots of parted out trucks around just depends wherw you live maybe soembody has one. Looks like rig shit is rigged up to me??????? Quote Link to comment
rsdaumer Posted February 27, 2012 Author Report Share Posted February 27, 2012 im in louisiana. i figured out one was the horn relay and got a new one. took the old headlight relay apart and nothing is burnt or anything, but its still not working. we could get the old one, and the new one, to work with the high beams and low beams on all the time, but not the low beams by themselves and be able to trigger the high beams. checked the switch in the cab and it it worked fine. Quote Link to comment
DanielC Posted February 27, 2012 Report Share Posted February 27, 2012 I do not have a 620, but I do have 521 trucks. The headlight wiring on the truck may similar, I do not know. The headlight relay on my truck has four terminals, with the following colored wires. A red with yellow stripe wire, supplying power, a red with white stripe wire, going to the high beams, and a red with black stripe wire , going to the low beams, and finally a smaller diameter light green with white stripe wire, going to the dimmer switch, on the steering column. Power is supplied to the common terminal on the relay switch, and to the coil of the relay, in the original Datsun headlight relay. The steering column grounds the light green with white stripe wire, and this makes the relay switch to high beams. The red with black wire, going to the low beam headlights is connected to the NC terminal on the relay. The Red with white stripe wire going to the high beam headlights is connected to the NO terminal. If you use a heavy duty Bosch cube relay, red with yellow goes to pin 30, and has a jumper to pin 86. The light green, with white stripe wire goes to pin 85. The red with black stripe wire goes to pin 87A, and the red with white stripe wire goes to pin 87. Quote Link to comment
rsdaumer Posted February 27, 2012 Author Report Share Posted February 27, 2012 thanks for the info daniel. my 620 has 4 wires, red supplying power, red/white, red/black and red/yellow. the red/black i believe goes to the high beams, red/white goes to all four lights, and red/yellow goes to the hazard control switch which links into the high beam/low beam switch. Quote Link to comment
banzai510(hainz) Posted February 27, 2012 Report Share Posted February 27, 2012 rsdaumer take the old relay and trip it(make it turn ON) and measure witb a ohm meter the main contack ends. if open then look inside the contacks. Somepeople just sand the ends with sandpapar Quote Link to comment
rsdaumer Posted February 28, 2012 Author Report Share Posted February 28, 2012 hey daniel i used your information and got everything working great. had to make a jumper wire from coil to com. thanks!! Quote Link to comment
DanielC Posted February 28, 2012 Report Share Posted February 28, 2012 Glad you got it working. So, a 620 headlight relay is wired just like a 521 with the same colors of wires? Quote Link to comment
rsdaumer Posted February 28, 2012 Author Report Share Posted February 28, 2012 nah theres no green wire, its a red/yellow wire that goes to the hazard light harness which goes to the switch Quote Link to comment
rsdaumer Posted March 2, 2012 Author Report Share Posted March 2, 2012 So the relay i ordered off of rockauto and had hooked up decided to burn up. the corner is fried and i have to tap it to get it to click out of high beam. just ordered a new one from autozone that has a lifetime warranty. ugh this truck is really making me mad sometimes Quote Link to comment
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