Headlight issue

[mysterymojo]

So my headlights arent working right. I have a 1974 620 pickup and the guy i bought it off of had some jenky ass stereo setup so i took it out got some new speakers and put a new deck with new wiring. the speakers and deck i installed work great. the car still runs no other electrical problems for the headlights. they were fine before i messed with the stereo setup and now they dont, so now im confused.

 

basically my headlights wont go on when i pull the switch out. if i pull it half way out my hazard lights/parking lights go on, but if i pull it all the way out the lights dont go on. the parking lights still stay on though. once i pull the witch all the way out then turn on the brights/high beam all four headlights go on fine. wtf. so i can drive with all 4 lights just not the 2 outter headlights.

 

i have no idea why this would occur after messing with the stereo wires. I didnt take anything out that wasnt attached to the stereo that should mess with it. the only thing i can think of is this;

my stereo is connected to a fuse in the fuse box that i have no idea what it does, maybe the headlights? and the stereo deck the other guy had in there was connected to an equalizer he had hooked up to some random speakers in a box on the floor which were attached to a switch that was also connected to a line that went directly to the battery and some after market fog lights he installed.

 

im wondering if there is some electrical loop that may have run from the fuse through the jenky stereo setup through the fuse back to the battery that is messing with the circuit.

the order would be from the fuse to deck to equalizer to switch to fog lights and battery then wherever and back to the fuse, or vise versa.

 

i have no idea...

anyone??

[Laecaon]

Maybe killed the low beam filament in both outer headlights... but unlikely.

[mysterymojo]

Maybe killed the low beam filament in both outer headlights... but unlikely.

 

 

 

yea i dont think so. the outer lights still go on when the beams are on. so all 4 bulbs are on. i even accidentally turned just the outer lights on by themselves. for some reason they went on for a few seconds then went off . its some thing screwy with the wiring.

 

maybe someone knows where i can find an electrical diagram for the wiring of the headlights? ill do a search myself to see if i can find something but if anyone knows, please let me know thanks

 

 

[datzenmike]

The only connection to the lights would be the (or the sensible thing would be) the dash lights so the stereo lights up at night.

 

I would remove the fuses and replace them while cleaning the clips that hold them. If very crusty, soak the fuse block in a vinegar bath over night , rinse and dry and install again. Fuses are unreliable and can't be trusted on looks alone. Just put in new ones to eliminate any intermittent frustrating problems with them.

[Shagy]

goto www.olddatsuns.com the wring info is there.

[datsunaholic]

My '74 (and my Mom's '73) both had quite a problem with the headlight relay, which is on the radiator core support between the radiator and the passenger headlights. The blade terminals get corroded, or the wires work loose. Later years moved the relay to a less wet location.

[mysterymojo]

ill look into all these suggestions. im wondering if maybe the fog lights are wired to that relay in the front some how. ill have to check for that

[pharouh]

Yeah,sounds like the relay or a dirty fuse holder. I had one years ago,that the parking lights would come on,but no headlights. I took the fuse and moved it back and forth in the holder-and they worked!.

[datsunaholic]

Or it could be the switch. I've had that happen too. Push it partway in and the lights would flicker.

[mysterymojo]

so now i have a new problem, all 4 of my lights are out. the regular headlights wont go on and the brights/high beam wont go on. the parking lights still go on.

 

i checked the fuse box to make sure all the fuses are in tightly and that none of them are broken. Im not sure what else to do. i would rewire the headlights if i knew how they were wired and im not sure how to read that diagram for the wiring.

 

anybody have any suggestions?

 

i know the bulbs arent burned out and sometimes if i leave the lights on while i drive they will flicker for a second or two. im pretty sure that either something in my wiring is loose or not connected right but i dont know where i should look.

[banzai510(hainz)]

unplug the fuse box then plug it back in.

620s I thinkis a switchable ground also like a 510.

Thats means if you have a test light. and ground it. then place the pointy end in back of lamp on the connector. the light should light up. Thats mean your + side battery is hooked up. Your missing a ground to turn the light on.IF you dont LIGHT UP then your missing power from batter thru the fuse to the light

 

Now Im not a 620 expert but I would find the relay and ck that. Maybe hit your hibeam switch. Do you hear it click? That means the steering wheel ground work. but doesnt mean the contacks are good. still need to ck this.

maybe pull the plug on th relay. and plug back in.

 

maybe there is a ground wire by the pull switch inside thats loose.

 

most times it just corrossion.

 

 

sometime

[datsunaholic]

Have you checked the headlight relay? You haven't mentioned that. It's the relay between the pass. side headlights and the radiator, on the core support, with individual wires. Every '72-74 620s I've ever had or seen had severe corrosion there since the relay gets wet in the rain, and traps dirt and stuff between it and the sheet metal. Usually it's just the spade connectors, I've cleaned them and made 'em work, though my Mom's '73 did have the relay disintegrate once.

[kelowg]

try a new fuse, had one that looked good but tested bad. solder inside fuse melted, probably cause of loose fuse holder