73 620 Turn Signals & Fuel Gauge

[Juan Valdez]

Good Evening Ratsun... my issue: on my way home from work today my turn signals stopped working while sitting at a stop light. I noticed a small puff of smoke from the clam shell.

 

Last week, my drivers side brake and turn signal (front and back) had stopped working. I checked the housings and all was good. No corrosion, bulbs are good. Grounds are good. Opened the clam shell and found that the wire for the left side had disconnected from the turn signal switch. Resoldered it and it worked great until today.

 

Today, I he checked the fuse block and found that the fuse had blown. Replaced it. Checked the turn signal switch and all is okay there. Pulled the flasher and a shook it a little and I could hear rattling in the case. No problem... Popped in a spare. Go to check turn signals, and the passenger side works good. I flip it to the driver side and pop goes my turn signal/flasher unit. When this happens, my fuel gauge stops working. How's that?

 

My hazards work fine, as do my running lights and brake lights. I just can't get my turn signals and fuel gauge to work now.

 

My electrical troubleshooting is not the best. I have a fsm, but I also have a baby sleeping on my chest right now. Do you guys have any suggestions of where to start once I get back into it tomorrow?

 

Thanks.

 

 

[Dat Lurka]

I hate electronics.

I know there are relays for those. And on your truck I THINK they are under the passenger side of the dash.

[Juan Valdez]

I hate electronics too. Shit is the black arts... Well, I got in my truck this morning and started it up to head off to work and my turn signals and fuel gauge worked until I got about three blocks from my house, when again, both the signals and fuel gauge went dead. I pulled the turn signal/flasher unit that I installed last night and it's dead.

 

I not going to dick around with it this week since work and baby dominates my schedule, so this Saturday I'm going to break out the multimeter and FSM and go to town since I have a starting point. I've been chasing down wiring gremlins since day 1 on this thing, and I'm at the point where I may just buy an aftermarket harness with extra circuits since my harness looks like it's been to hell and back.

[Juan Valdez]

Well, once again my turn signals and fuel gauge is working. Thank you Jesus! It's a miracle!!!

 

Actually, I jiggled the connectors on the back of the fuse box. Going to check that out, vinegar bath, whatever, this weekend. I'll post my updates just to keep the thread/issue/resolution relevant and complete.

[datsunaholic]

Sounds like corroded connectors to that fuse. The turn signals and gauges (and reverse lights too) are all on the same fuse. When you flip on the turn signal, it's a bigger load, and the corrosion oxidizes making an insulator. Wiggling wires or spinning the fuse cleans that off and it makes connection, until it happens again.

[Juan Valdez]

Thanks for the explanation, datsunaholic. I'm just going to go through the whole dash harness and clean everything up. I've got an extra fuse block too that's in pretty good condition that I may swap out too. The one that's in the truck now is pretty corroded and dry rotted.

[Dat Lurka]

Don't forget to check the bulb socket.

#1 datto light failure

[Juan Valdez]

To update this, I soaked the fuse block in vinegar overnight (like everybody recommends) on Friday and reinstalled Saturday afternoon. I also replaced the fuses - they all looked good, but I have no idea how old they were, so I rather know that I have new fuses in there because the old ones could be garbage even though the filaments look fine. The terminals still looked a little hazy after soaking, so I went after them and the connectors that go to the fuse block with a little emory board. Hooked it all back up and I have no problems now. Turn signals function properly, and my dash lights work now.

 

The entire harness itself, from the battery all the way back to the tail lights is a mess. I do need to go through the entire thing to make sure there are no other gremlins. I also need to get some larger gauge ground wires for the battery>body, batter>engine, engine>frame/body, etc. My headlights dim when I turn my turn signals on, I have random loose wires hanging all over and some sections of the harness(es) look like they were spliced together by a blind paraplegic.

 

An unrelated funny thing happened last night that made me want to throw myself off a cliff in despair. When I got home from work my damn brake lights wouldn't turn off - no matter what. I thought to myself, maybe I "over-fixed" my problem. I disconnected the brake switch, which was hotter than a steaming pile of shit, and went inside and cracked open the FSM. Took what I have from there and started testing shit on the truck. Found nothing wrong. Connections were all good, no wires melted, everything is in place where it should be. So I hopped on the interwebs and started searching on Ratsun and found that the stupid plastic thing on the actual brake pedal arm had disintegrated, so the pedal was no longer interrupting the current when the pedal was released. I jammed a 10mm screw in the hole and filled it with RTV. Problem solved. I love Ratsun. Thank you guys for knowing more than me.