1981 HJ47 Electrical Problem (1 Viewer)

[Capitol Troopy]

Greetings, Troopy team!

My 1981 HJ47 all original Troopy has an electrical problem that‘s hard to nail down. My local mechanic has given up and recommended an entire wiring harness rip and replace. I am not yet convinced that’s necessary. The problem over the last two years is as follows. After easy start and pleasant drive, headlights, turn signal, and ignition seem to fight each other. In most extreme occasions the Troopy continues to run after turning ignition off and removing key. On occasion all gauges, lights, and other electric simply shuts off while driving. I think I saw a thread a year or two ago about the ignition problem.

Can you help!

 

[fjwagon]

I had electrical issue with an 1980 h47, H engine. I had a glow plug issue. Sometimes it would not glow. A couple of times it would not start. I reseated connectors and would go away but come back. I did the normal component checks. Did not find any shorts or bad components. My conclusion at the end was the harness had an issue. You have to remember some of these vehicles are sometimes used like farm implements or worse. Anyhow, since the one own did not have the illuminated headlight switchblike the US version, I wanted to splice the new headlight switch into the circuit . So I disconnected all the connectors inside the cab and under the hood. Snaked out it and inspected the ignition and glow plug circuit and sure enough I found a cold solder joint. A cold solder will beep on a continuity test but under load it does not have the current capacity so the circuit stops working. I spiced the new head light switch and did a "work around" by using a pair of visegrips to complete the circuit. This is not your typical fix. I really wanted to use the correct color wire but did not have any so hence the vise grip repair. My advice or suggestion is check for "opens" or bad components but at the end of the day if you don't find any culprits, removing part of harness and peeling the harness apart and start checking common points for grounds and 12v. I have seen some harnesses where the copper wires have corroded from running them on salt roads in the winter. I hope this is not the case. Anyhow, sorry for the long winded response

 

[duncanrm]

Lol.. an entire harness replacement because he cant identify the problem. He sounds incompetent, if nothing else he should be giving you some roadside diagnostic tests to perform when the issue occurs in an attempt to narrow it down. The systems you've described (indicators, headlights, ignition) have different fuses - a common point for these is the ignition switch though. Seems a likely place to start. More information about the symptoms would help though.

As to the engine not shutting down intermittently - this is often the EDIC rod being a tiny bit too short - if you navigate to my 2H/12HT page (Toyota Diesel Documentation - https://sites.google.com/view/toyotadiesel/home) and scroll down to Common Problems you'll find a link that discusses this issue with the EDIC rod length.

Additionally you'll also find a poster sized HJ47 wiring diagram at that link, take the time to study this.

Your most important tool in diagnosing an electrical fault on an old Landcruiser is a Test Lamp with an incandescent bulb. When your problem reoccurs I'd be immediately using the test lamp to look at the fuses for Turn and Headlight to see if there getting power or not. A digital meter is really only useful for measuring exact voltages, voltage drop, current and resistance - never use it to look for the presence of 12V+ or earth.

I'd also test the hazard lights when things start playing up.. its on a different fuse (permanent on via STOP/HORN), it may give some additional insight.

I'm also curious on how its affecting your "ignition", is the engine bucking/stopping then starting? If so this is also a common EDIC fault and is usually caused by poor body/engine earths (see the page above, under Common Problems again).

 

[45Dougal]

Certainly sounds like a high resistance in a connection at the Ignition switch, or fuse box to me.
I'd pull both out and check for signs of melted wires and corroded contacts.
Both are pretty easy to try.

 

[whitey45]

Fwiw, I have an 81 hj47 and have some of the same issues. It is my fuse box, it has become soft over the years , if I push on it, it flexes and some circuits go dead. While you have it running, manually move and push on your fuse panel, or just move wires around, easy way to narrow down an issue. The edic does get power from the fise panel, and can cause a shut down!

 

[duncanrm]

Fwiw, I have an 81 hj47 and have some of the same issues. It is my fuse box, it has become soft over the years , if I push on it, it flexes and some circuits go dead. While you have it running, manually move and push on your fuse panel, or just move wires around, easy way to narrow down an issue. The edic does get power from the fise panel, and can cause a shut down!

Its really worth removing each fuse in turn and scuffing up the internal surfaces of the brass holders with a bit of rolled up sandpaper.. at the same time replace any fuses that have corroded caps.

 

[whitey45]

Yes, agree, a fuse can look prefect until you pull it out and has corrossion and white powder!