Little electrical problem

[Guest DatsuNoob]

So I discovered this morning that I have no brake lights, no horn, or emergency flashers. Horn was working sweet a week ago, as were the brake lights. First thing that popped into my head was to check the fuse, since they all share the same one, and it was still solid. I popped my tail light lenses off and saw that both of my brake lt bulbs were out. I swapped the other marker light bulbs into the sockets which were a little bigger(1157's) but figured they might work since the socket size is the same, and I got nothing. I checked the wiring diagram in my repair manual and it wasn't much help, because the tail lights terminated into a box on the pic and wouldn't show which wire was ground, so I could atleast see if I had a bad ground. All my wiring is pretty crusty to start with, but can anyone tell me what color, or the location of the grnd wire is? Any other suggestions on what to check? Wiring and electrical has always made about as much sense to me as a fast conversation in chinese, but I'm willing to take a stab at it, was just looking for a little guidance from someone a little more inclined in that area. Thanks

[datzenmike]

black

 

Get a circuit tester, about $5, and clip one end to ground and touch the probe to both sides of the fuse. It may look good but never trust looks alone. You should have 12 volts on both sides. There's no way your horn, 4 ways, and rear lights all failed a the same time. You are not getting voltage to them.

 

My wiring diagram for the '76 shows tail lights on a different fuse than the horn??? (could be wrong?) Check them all I guess.

[Guest DatsuNoob]

thanks mike, but all the wrieing looks dark brown, either from old age or my color blindness or both. Still scratching my head....

[Pacific coast Datsun]

I went through a TON of electrical problems on my 620 & still have a few minor bugs to work out still. You may need to remove some or all of the wire cover & look for shorts or any exposed wires. Start @ the fuse block & go from there. It also could be the fusible link. http://www.the620.com has all the diagrams there,print them & take them to the truck as you look for the problem. :confused:

[hang_510]

check under the fuse box too.

corrosion at many connections is very common.

especially when some hack spliced the wires by twisting them and then taped em closed-thats it :mad:

this was how the 0 gauge + wire from the battery to the starter was under the carpet :eek:

 

on my 2dr i cleaned or replaced every connection.

i replaced quite a few spade connections, i had NO more light issues after. :cool:

[Bleach]

I've had fuses look solid but were blown right at the end where you could hardly see. I think you should buy some new fuses and replace them all anyway. Its worth it for a couple bucks.

 

get the proper tail light bulbs while you're at the store. Steal some money from Mel if you have to!

[hang_510]

^good point.

ive seen fuses that looked good, but had melted the connection in the caps. give em a twist...if they do, replace em.

[banzai510(hainz)]

Do as the 2 above people mentioned just change all the fuses with new ones.

 

anybody with a old datsun should do the same if they look like they never been changed.

 

I had my taillights outs and didnt notice it but notice my dash lights did not work. Well a Cop pulled me over.!!!!!!!!!AGAIN!!!!!!!!!!! for the 50th time!!!!!!!!

 

well it was a fuse that looked good but the end inside was separated. it was on/off again, if I held the fuse together it would work.

 

This is of caoarse most stock datsun wiring has not been hacked into then I DONT KNOW. I DONT KNOW MR HAND(fast times at RidgemountHigh)

 

 

On the 521 you poull the light out from the twist sockets in back. You dont have to pull the lenses off. I dont know if same on the 620s but would assume it was the same

[hang_510]

I DONT KNOW.

 

im leaving that up there all day and giving you credit for it!

[Guest DatsuNoob]

hmmm, well I checked the wiring to the tail light housings and it looks pretty nasty. The old man who owned the truck before me has a bunch of stuff either disconnected, bypassed or bridged together. It's a friggin mess! He also did the same with the stock carb wiring, and a few wires behind my stereo I'm unsure of what they go to. Must've considered himself a real hotshot hack electrician. It's an electrical nightmare for a guy who barely understands the concept of electronics. I'll go get a test light tomorrow and get into it this weekend and get back to you guys. I went to Baxter's and they tried to sell me on one of their Painless fuse block wiring kits. Sounds like alot of work I dont want to undertake since only one fuse terminal is affected.

[OL YELLER]

]

 

Ah come on "NOOB", you just know that rewiring your entire truck would be and adventure worth getting excited about!!! LOL[http://i114.photobucket.com/albums/n275/ronkelley/OLYELLERSInnardscopy.jpg[/img]"]http://

[datsun dreamer]

Hey ron, Thats how my '73 is gonna look in about 2 weeks1

[datzenmike]

Here's my swapping in a complete 720 4X4 harness...

 

http://i138.photobucket.com/albums/q251/datzenmike/img005-1.jpg[/img]"]

 

..720 dash/heater/steering column.. You can see that I even had to move the wiper motor. But I now have 15 fuses, a cool dash (that you can read at night) with tach and clock, variable pulse wipers, 4X4 voltage and oil pressure gauges and a huge glove box.

 

Go to a yard and get the rear harness between the lights, that plugs into the one that goes forward to the cab, hell, get that one too. It unplugs under the pass seat and threads down through the floor and is clipped to the frame. Just take your time. The rear one has all the light bulb sockets on it as well as the side marker lights. If I had known I could have pulled the '78 harness complete from my parts truck a month ago before tossing it.

[Guest DatsuNoob]

hmmmm.... I feel sorry for you fuckers! HAHAHAHA:D Whaaat a friggin NIGHTMARE!!!! Wiring sucks and I hate it! If it turns out to be something more complicated than anything I can figure out on my own, I may be inclined to take 'er in(as much as I would HATE that), or offer one of you guys some $$ to do it for me, since I know electrical about as well as I can speak Swahili. Still haven't had much time to get into it as deep as I might like(or not like :eek:), been working long hrs.

[datzenmike]

hmmmm.... I feel sorry for you fuckers! HAHAHAHA:D Whaaat a friggin NIGHTMARE!!!!

 

You're right, that was fucked up Ah-ha-ha-ha Got in over my head but kept at it and saw it through. Learned as I went along and it made me bold enough to do other stuff like a straight front axle. It is scary sometimes but pretty cool when you get it to work.

 

Mrs. datzen catches me staring at my truck sometimes.

[OL YELLER]

ya know I was kinda shocked when I first decided to tackle that job...but, I got the ol manual out and used those highlite markers to follow my progress, and damned if that thing didn't go pretty well....I did that about 3 years ago and it took me about 2 weeks of 3 hours a day, AND about 3 different harnesses that I salvaged at the J/Y...but it did work out well...just start with one wire (the color code makes it quite simple really) and go to its stopping point, then another then another, etc......now then having said all that: I would not really want to do it again!..But the satisfaction of knowing that I did it and knowing that my 35 year old wiring is in good shape is incredible.....ya know though, I have a friend that used something like the "painless" harness to rewire his little Ford coupe. I might be tempted to go that way too...those wires are marked every 6 inches or so..hmmmmmmmmmmmm something to ponder.....

[Guest DatsuNoob]

yeah, I guess I'm double screwed being electrically illiterate AND color blind! :DHave a hard time with separating reds from browns, or greens from browns, orange and yellow, but especially blue and purple. Painless might be the way to go should I decide to replace my entire electrical system, but for now I think I'll just try to find the short or break in the wire, from the brk lt, horn, emerg flasher circuit. For now she sits, kinda sad because she runs great, just not trying to get myself ticketed. I thought about driving it and just switching the headlights on when I hit the brakes, so my rear markers come on, giving me the appearance of brake lights, but I dont know about all that.:P

[Guest DatsuNoob]

I got some brittle wires connected to the tail lights, they're all pretty crusty actually. I got 2 big spools of 14 g wire(black, white, and gray). Time to go bust out the soldering iron and shrink tubing :) Probably a good place to start.

[banzai510(hainz)]

I would first just ohm out the wires.

 

Did you ever replace the fuses and ck the fuse box and the connections. Sometimes just removing the connector and putting back on will fix it.

[Pacific coast Datsun]

I agree w/ Hainz, try the easy stuff 1st. The fuse block in my 620 melted from behind & i lost power to a few things.

[datzenmike]

I would first just ohm out the wires.

 

Did you ever replace the fuses and ck the fuse box and the connections. Sometimes just removing the connector and putting back on will fix it.

 

WHAT HAINZ SAID!

 

Get a little test light with a clip. You ground the aligater clip and touch the probe to the wire, if there's power it lights up. Helps you to 'see' electricity. Likewise you can clip to 12 volts and follow a ground wire. Best $5 spent.

 

Sometimes just wiggle the connector where the rear lights plug into the main harness at the rear pass side frame.

[banzai510(hainz)]

If it was working before it can be made to work again.

 

If you lost power to other stuff its a main power issue I would think.

Probaply dont need to trace wire back to the tailights if you know now the horn dont work up front.

[Guest DatsuNoob]

fusible link then?

[datzenmike]

Not fusable link or there wouldn't be any power to the ignition switch. I looked at my wire diagram and traced the runs and YES (sorry) the 4 ways, brake light, and horn share the same fuse. NO WAY they could all fail at the same time. The fuse (15 amp) is blown even though it may look OK.

 

Replace: Works?

YES... fixed problem.

NO... somewhere there is a wire touching to ground.

 

Try disconnecting the tail light harness plug under the pass seat to see if this cures it.

[tnip]

not to hijack the thread but there was mention of a painless harness.... i've got one of these with the intention of putting in my 521 in place of the rat's nest that the PO left me with... has anybody used one? and also, how long does it take to remove all the old wiring and rerun the new wiring, say with a new stock harness?