A 720 2WD with a few electrical issues

[atticusprime]

I have a 1984 720 2WD that's an electrical nightmare at the moment. I bought it a few months ago for a daily driver/project and it's started out mostly as more of a project the more I look into it's problems.

• The headlight switch works only if it's twisted in a certain way while holding the outer cover on the column
• The radio seems to be a replacement of a replacement of a replacement... and the last guy who did it just used a couple of terminals for the ground to the whole radio
• The battery charges... most of the time... (possibly just a bad alternator)
• I have a fuse that routinely blows which controls the turn signals, indicator lights, and some other stuff. The only indication I get it when the dash lights are still on, the truck is still running fine, but the battery light is on and the signals don't work anymore. While extremely disconcerting, I don't think it's effecting much with the truck running or operating other than being a pain to figure out what part is wired wrong.
• One of the fuse slots in the block shows signs of having been shorted out by something. I assume, after that, someone took out the old fuse (if anything was left) and changed the wiring around in order to 'solve the problem'.

Right now, my plan is to not necessarily replace parts but to make/build a switch module to control the basics (headlights, start, etc). If I follow that plan though, it means that I'd have to tear apart the dash in order to do that; so, for the time being, help of any sort would be greatly appreciated to fix or otherwise get the truck into a more reliable shape.

[ggzilla]

So you aren't going to fix it, but instead alter the wiring even further?

 

The only problem with the wiring infrastructure seems to be the blown-fuse problem. Find the short is what I would do. Process of elimination.

 

Test the alternator. Check the brush length.

[atticusprime]

So you aren't going to fix it, but instead alter the wiring even further?

 

The only problem with the wiring infrastructure seems to be the blown-fuse problem. Find the short is what I would do. Process of elimination.

 

Test the alternator. Check the brush length.

 

Nah, I'll fix the problems as I find them. I'm a former aircraft mechanic/electrician that's just beginning to work on things that don't fly above the ground. ;) So the troubleshooting part is quite easy, but I guess I was a little pampered working on aircraft since practically every wire has a lot more info about it than what I've seen with cars. Right now I'm looking for good places to start the troubleshooting process.

 

The switch module is more of a longer term project than anything else. The more I know about the original wiring, the better I can make decisions on how to work in the switch module.

 

Thanks for the help!

[ggzilla]

There are tons on wiring info in the Nissan factory service Manual. A master wiring diagram, plus schematics and diagrams for the individual systems. Get one for the specific year of your truck.

[Guest kamakazi620]

Nah, I'll fix the problems as I find them. I'm a former aircraft mechanic/electrician that's just beginning to work on things that don't fly above the ground. ;) So the troubleshooting part is quite easy, but I guess I was a little pampered working on aircraft since practically every wire has a lot more info about it than what I've seen with cars. Right now I'm looking for good places to start the troubleshooting process.

 

The switch module is more of a longer term project than anything else. The more I know about the original wiring, the better I can make decisions on how to work in the switch module.

 

Thanks for the help!

Do yourself a FAVOR go to junkyard find 83-94 720,TAKE the wiring harness swap them Done and DONE..............

[datzenmike]

Turn signals and headlights are in the same switch assy. Get one from a junk yard it will likely fix the blown fuse problem too. That's 3 for the price of one.

 

I have had 720 fuses get hot and this softens the metal contacts which grips them leading to more heat and the plastic melts. I cut a fuse box out of a wreck and using a hair pin released the push in connectors that hold the fuses one at a time and slowly replaced the fuse box. The two bad wires I had to trim and solder to the two good new leads.

 

Alternatively you can replace the fuse box and the major harness back over to where it plugs into the firewall behind the glove box. The dash, ignition, taillights plug into it.