Lame electrical problems (lights)

[hacked521]

Upon finishing up my truck (521) to go get it registered i ran into a giant dilema. The turnsignals dont work, the head lights dont work and now for some odd reason my hazard lights dont work. I checked for a bad ground anywhere, i replaced all the fuses. I opened up my manual to look at a wireing diagram and follow all the wires to make sure they didnt get chewed up and were plugged in the relays correctly and the switches correctly. Its extremely frustraiting and am near to completely rewire the truck because of it.:mad: Any help would be great.

[AtomChurch]

I have had this problem twice. the first time it was a ground thats on the steering collum and there is a screw that holds the turn signal switch on, also it was because I lowered my steering wheel and I used these lame aluminum spacers that made a bad connection.

 

this last time I had a short in my wiring and I still have it but it goes off and on. its a short in one of the grounds somewhere after the fuse box all the way to the lights somwhere. It would be a quick fix did I not have to untape it all.

[hacked521]

allright, ill have to try the ground screw on the steering collumn. Hopefully it works because ive been chaseing this problem down for about two weeks straight now.

[pope_face]

Blown fuse? Blown bulbs? No bulbs? No fuse? I would start there... Sometimes it's surprisingly easy to overlook the simplest bits...

 

Other than that... get a voltmeter and start checking power at all relays/connections/switches. If you're using the stock switches then they might just not be connecting properly.

 

I just noticed that you replaced all the fuses, so ignore that bit. But, bulbs?

[DanielC]

There are several lighting circuits on a 521.

Headlights are a seperate circuit on a 521. the Headlight circuit has it's own 20 fuse, always hot, and had a big red wire coming off the back side of the fuse block. This wire goes into the cab, behind the windshield wiper motor, and has a plug by the outside of the glovebox that joins the engine room wiring harness to the cab wiring harness. The wire then goes to the light switch, and back to a plug by the glovebox, and back into the engine room. It might be a different connector in the plug, or the same one. There are several plugs by the glovebox. The switched power then goes to the headlight relay, and is applied to the coil in the relay, and one set of contacts in the relay, and out to the headlights. The headlights have a black wire on them to ground them, and that wire comes back to the voltage regulator, and grounds there. When you put the turn signal switch in high beam position, it grounds the coil in the headlight relay, and the relay switches from low beam to high beam. The headlight circuit on a 521 is different than a 510. A 510 switches the high and low beam headlights in the ground for the headlights.

All the other lighting circuits use plugs in the same location by the glovebox to connect the cab wiring harness to the engine room harness. The engine room harness also has two plugs down by the starter for the rear harness.

Tail lights, side marker lights, licence plate light, speedometer lights, and engine room light all get power from a 10 amp fuse, always hot. Most of the lights are always grounded, and come on when the light switch is pulled out to either position. The engine room light grounds through a switch that the hood holds open when the hood is closed.

The brake light circuit is always hot, it has a switch that is closed when the brake pedal is pressed, or a pressure switch that closes when the brake system gets some hydraulic pressure.

The hazard switch has always has power going to it, for the hazard flashers, and when the key is on, power for the turn signal flasher, and then the turn signal switch on the steering column. Two different power supplies go to the hazard flasher switch. One is always hot, one is switched with the key.

Power for the turn signal switch goes through the hazard switch, through the turn signal flasher, and then to the turn signal switch. and then to the selected turn signals, and the indicator lights in the speedometer. The front turn signals ground by bolting to the body. The rear turn signals ground with a wire from each taillight assembly forwars to the frame of the truck

When you turn the hazard lights on, power is removed from the turn signal circuit.

Hazard power always hot, and goes to the hazard flasher, through thew hazard switch, and then goes to all four turn signals, and the speedometer turn indicator lights.

The cabin light is always hot, and grounds when you move the switch on the light. If you have door switches for the cabin light, they also just ground the cabin light at the door switch, similar to how the engine room light works.

Hope I did not miss any lights. That is how the lighting system on a Datsun 521 works. Simple, isn't it?.

[pope_face]

Wow... Daniel, that's really good. It's probably not all that important to most folks, but it'd be nice to have that in the FAQ.

[hacked521]

thanks for the info on the light circuitry. i got the headlights to work but that was just because of the po's missconnecting of a relay and light switch, i must of skipped over it when i did the first check. The light circuitry will help me out with the turning signals hopefully, Im going to replace the bulbs in those tomorrow. The brake lights, low beams and high beams work now.

[fiveNdime]

If you got power to the relay try jumping the relay. I've had bad relays before and it was extremely frustrating, even new ones have been bad on me.

[dat521gatherer]

yeah check the plugs at the turn switch and the firewall. tweak the terminals tighter if needed or corroded. do your cluster signals light up at all. if they do you may have grounding problems at the sockets. try using a test light to track the problem.

 

i have a blinker problem i haven't worked out. left blinker stops blinking when i step on the brake, but if it's raining it will blink very slow and tries to make the brake light blink. i'm about to swap the whole damn rear harness out. brake wire fell off the pedal switch and the blinkers worked fine till i noticed the brakes weren't coming on. back to the same old problem. and i dont think it always did it. i keep saying i'm going to visit a local member to help me on this one it drives me crazy:mad::mad: not trying to thread jack you just letting you know your not alone.

 

my blinkers didn't work on my other 521 cause i didn't plug in the blinker plug good enough. generally wiring problems on these are ez. good luck

[DanielC]

I put a ground wire on my left rear taillight assembly. From the stud on the left taillight frame, to the frame of the truck. Stock, there is a ground wire from the right taillight assembly, and I think there was not a seperate ground for the left taillight. So current from the left taillight has to go to the left taillight frame, through the screws holding it to the bed, into the right taillight frame, into the stock ground wire on the right side, and then to the frame of the truck.

[hacked521]

well i tried everything on the turnsignals..i cant get them to work. I have headlights but lowbeams wont come on, i tried taking the plug off the back of the switch to see if one of the wires were missplaced in the socket and all the wires ended up pulling out of the sunroted socket. Pissed me off :mad:. I just think that the wireing hates me. Im starting to contemplate on makeing my own harness for the entire car because all the wireing ive done works. Its justthe stock wireing thats screwing with me. I dont know whats up with the turnsignals. Ive replaced the actual unit and i checked for power at the actual turn signal. I also did the grounding screw on the turn signal mount. Im getting so frustrated with this part of my build.:mad:

[DanielC]

Power for the headlights goes from the battery positive, to the headlight fuse, into the cab through a connector plug by the glovebox, to the light switch, back a connector plug by the glovebox, and then to the headlight relay, for both high and low beams. The relay then controls if the power goes to the high beams, or the low beams. The Red wire, with a black stripe, coming from the relay going to the headlights is low beam, the red wire with white stripe is high beam. The headlights ground to a black wire that goes back to the voltage regulator, and ground at an eye on one of the voltage regulator mounting screws.

Switch the position of the Red with Black wire and the Red with White wire on ther headlight relay, and see if the other set of lights come on. If the other set of lights come on, the light wiring is good, and the relay is probably bad.

With the turn signals, is the flasher good? also all four turn signals have to be good, or the flasher may not flash.

[datzenmike]

As Daniel said earlier the 4 way has to disconnect the regular turn signals in order to flash all lamps. The 720s have a problem with their switches... seems when you turn the 4 ways to OFF, the switch goes too far and goes past the usual connecting up of the turn signals and they don't work. The fix is to move the 4 way switch just slightly toward the ON position and this connects the turn signals back up. Try this on yours. Maybe turn ON and OFF several times to clean the contacts.

[DanielC]

In my post on 04/04/08, I overlooked the fact that on a 521 the power for the turn signals go through the 4-way flasher when the 4-way flasher is off.

Thanks, DatsunMike for pointing that out!

Do the 4-way flashers work on all four corners? If not, fix that. The stock turn signal flasher needs two working turn signal bulbs to work correctly.

With all four turn signal lights working (turned on), put a block of wood, or have somebody else step on the brake pedal. This should not affect the 4-way flashers.

With the brake pedal pressed, and the engine not running, put the transmission into reverse. The back up lights should come on, and not affect the 4-way flashers, or the brake lights.

If turning on one set of lights affects the other lights in the taiilights, you have a bad ground from the taillights to the frame of the truck.

You can make several short jumpers with 1/4 male spade ends on them. The jumpers can be substituted for turn signal flashers, 4-way flashers, the brake pedal switch, and the transmission reverse switch, if you need to. A very handy thing to have when trying to figure out weird electrical problems.

[fisch]

HAcked, did you run some sandpaper in the actual blinker lever switch on the column? Mine looked fine up there, no noticable corrosion, but I hit it with some sandpaper, and it worked! I was psyched it was as simple as that. Same thing with my horn. Looked fine on inspection. But didn't work. Hit the contact ring with sanpaper, and scared the shit out of me when it went off.

[hacked521]

yeah fisch i did hit up the horn and the contacts for the headlights and the actual turnsignal contacts with some 180 sand paper. They actuall had a little bit of surface corrosion on them. No worries though, im making my own harness. I would have to anyways because im taking everything and making them into toggle switches.

[Cuts metal like mad]

late post I know... I had this problem on my last 510, it was really strange and I took my multimeter to EVERYTHING, the headlights are tied into the turnsignals through the fuse box and I checked for continuity through the entire thing, for some reason it was blowing fuses on one side of the turnsignals and that is what would cause the everything to go out, I dissasembled the entire fuse block and cleaned it up and checked for shorts and and everything was good, so I reassembled it and put it back in, new fuses and tryed it out... popped the same fuse, at this point I am very frustrated... so I start unplugging everything in those circuits except for the headlights, put another new fuse in and pop again its GOT to be the headlight, I had planned on upgrading the headlights and the harness as described in another post here; http://forum.ratsun.net/showthread.php?t=4459 so I cut the headlight harness out... and presto no more popped fuses plug everything else back in and we're good.

[hacked521]

I ended up just making my own harness to solve the problem. Everything works now. :D Thanks for the reply anyways.