Datsun/Nissan finatic Posted November 30, 2014 Report Share Posted November 30, 2014 Hey guys I swapped a 78 620 dash and harness into a 77 620. Everything works except my low beams. From what im learning is the 77 uses a headlight relay and the 78 does not. Is there a way to modify this easily or am I in trouble Quote Link to comment
datzenmike Posted November 30, 2014 Report Share Posted November 30, 2014 Was the turn signal and dimmer switch also changed? Both are different or wired differently. The '77 grounds the relay to turn it on/off. The '78 Connects power to either the high or low beams directly. Quote Link to comment
Datsun/Nissan finatic Posted November 30, 2014 Author Report Share Posted November 30, 2014 ok I changed the directional switch on the column but did not change the dimmer. Do I have a way out here? Quote Link to comment
DanielC Posted November 30, 2014 Report Share Posted November 30, 2014 If the 77 uses headlight wiring, and a relay like a 521, the whole of the dash wiring, as far as the headlights go, is to supply power to the headlight relay. If you power what would be pin 30 on the stock 521 headlight relay, the headlights come on, low beam. The headlight relay coil is grounded by the switch, on the turn signal, at the steering column. When the headlight relay coil is grounded, the relay switches to high beams. 521 headlight relay wire color code, the 620 may be the same. Thick red wire, with a yellow stripe, switched power to headlight relay. Thick red wire, with a white stripe, high beam lights. Not quite as thick red wire, with a black stripe, low beams. Thin light green wire, with a white stripe, relay coil ground, goes to turn signal switch. Quote Link to comment
datzenmike Posted November 30, 2014 Report Share Posted November 30, 2014 ok I changed the directional switch on the column but did not change the dimmer. Do I have a way out here? Isn't the turn and dimmer switch one and the same? Quote Link to comment
Datsun/Nissan finatic Posted November 30, 2014 Author Report Share Posted November 30, 2014 the dimmer is a knob you twist on the dash. The turn signal is on the column. Quote Link to comment
Datsun/Nissan finatic Posted November 30, 2014 Author Report Share Posted November 30, 2014 When I unplug the relay under the hood I was able to jump or splice to get low beams but when I switch to High beams three terminals, total of 5 become hot 12v thought maybe I could get away with somthing like that? Quote Link to comment
datzenmike Posted November 30, 2014 Report Share Posted November 30, 2014 Sorry by dimmer switch I mean the high to low beam switch. It's on the turn signal stem. Quote Link to comment
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