Hazard lights cranking engine - “fun” gremlin

[cruisermatt]

Thought this would be a good share. Definitely one you haven’t seen before - when driving my FJ62 the starter randomly engages and tries to crank the engine, and stays on after shutting the engine down and pulling the key out. When it does this, both the turn signal arrows on the dash illuminate and stay liiuminated while the starter is cranking but only when the starter comes on it’s own (Hint 1).

While reinstalling the column clamshell and ignition switch after testing it (it tested fine) I bumped the hazard light switch which to my surprise engaged the starter. (Big hint 2)

Ok, pull the whole dash and AC and expose the main body harness. While proding around I bumped the two wires that go to the brake light switch on the pedal (for whatever reason I replaced the Toyota connector on the main harness with two spade connectors years ago, don’t really remember why). This also engaged the starter. (Hint 3) I assume using brake pedal would also cause this since you essentially bridging those wires when using that switch.

Pulling the STOP and HAZ fuses stops the problem from happening when the switches are pressed, however the starter still comes in randomly when driving.
I believe the starter solenoid trigger wire is getting power from both the power wires to the brake and hazard lights.

That’s where I’m at now. I am poking around the dash harness looking for some burned or chaffed wires. I will find them, I would like to avoid the shortcut of just remaking those circuits. I will share my findings!

 

[OSS]

That probably takes the cake for floating grounds. My guess is it's a ground problem, and yes, there's probably a short and very likely a bad electrical ground somewhere.

 

[FJACS]

Got to the part of the harness that passes through the firewall yet? In the corner behind the inner fender?

Mine needed a bit of help in that area.

 

[cruisermatt]

It’s definitely the worst electrical gremlin I’ve seen on on Land Cruiser factory wiring. This area is one of the very few I haven’t modified or even really messed with. This is the first time the dash board has been removed from this truck.

Both the dash harness grounds (on each A pillar) look good visually at quick glance. That was last night as it was getting dark though.

 

[cruisermatt]

Got to the part of the harness that passes through the firewall yet? In the corner behind the inner fender?

Mine needed a bit of help in that area.

Good idea. I have not gotten there yet but I will check there.

 

[NeverGiveUpYota]

Gremlins are really such little bastardly creatures.... hope you find the worn area of wiring. Will be interesting to see where it is. Like @FJACS said, I would imagine most of our trucks wear at similar areas along the harness simply from years and years of vibrations as well as areas where the protective grommets have been tweaked out of place by previous owners tugging and pulling.
Sucks you had to pull the dash out. But while your in there....

 

[cruisermatt]

The big firewall grommet on the passenger side looks fine, I don’t think that is the issue.. after thorough visual inspection of the whole dash harness there isn’t anything that sticks out externally.

I would like to avoid pulling the whole dash harness, mostly because of the work I’d have to do in the engine bay to get the headlight harness out with it, however there are many unused wires now since I don’t have 3FE EFI or the automatic or vacuum-shift T-case any more. It would be nice to pull all those wires COMPLETELY out instead of just snipping the connectors..
I need to decided whether to pull the whole harness and un-loom it
or just unloom it in the truck in the main dash section.

Also, I don’t have the schematics in front of me at the moment, but is the Circuit Opening Relay (passenger kickpanel FJ62) supposed to click when the brake pedal is used? I don’t think it’s supposed to...

 

[tmxmotorsports]

I don't remember anything clicking when i hit the brakes in my 89 fj62 i drive it daily

 

[FJACS]

Pulled open a 62 diagram today while I was in the garage.

What does your circuit opening relay do at this point? Do you still use the factory wiring to the fuel pump?

 

[cruisermatt]

Pulled open a 62 diagram today while I was in the garage.

What does your circuit opening relay do at this point? Do you still use the factory wiring to the fuel pump?

Good question.
At this point, I don't think it SHOULD be doing anything... I WAS using the factory wiring to the fuel pump, I spliced my wiring to the wire that comes off the circuit opening relay and then it was factory from there. However I was randomly loosing voltage to the pump and it was between my splice and the tank (Toyota wiring that runs from the COR to the tank). I abandoned this and have a new separate circuit for the pump now.

Interestingly enough...

The same day that that wiring failed was the same time I started having the starter sticking on, engaging on on its own, etc.

 

[FJACS]

So:
-Original fuel pump wiring went bad;
-Brake pedal makes the starter engage;
-hazards make the starter engage;
-circuit opening relay clicks with the brakes.

Possibly you’ve got an issue in the drivers rear quarter with the wiring and connectors in that area. Red/green could potentially be mixed in with the light wiring and click the COR relay.

 

[cruisermatt]

That’s gotta be it. I had to do a major repair in the driver’s rear 1/4 about two months ago (I completely melted through that section of the harness with my extremely high tucked exhaust) and had to splice every wire back together (I did this on the truck without removing that harness section, and outside at night too )
Very possible I mixed a connection but all lights worked, I haven’t check since I made the repair though.

I will get a used replacement harness for that section. The fuel pump wiring doesn’t run though there though, does it? I was driving when I melted that taillight harness and didn’t have a fuel issue.

 

[cruisermatt]

Ok, update.
Pulled the tailight harness and found all sorts of fun things.
This is the harness that I spliced every wire back together under the truck in the dark. It has two grounds, a brown wire (for the fuel guage sender) and a white wire with a black stripe, which is the ground for all the tailights. The only wire that had an issue was that W-B ground wire which had zero continuity from where it bolts (“center back panel per the FSM”) to the connector where it connects to the rest of the body harness. So, if that’s the case, how the heck were the tailights working (they all worked fine after I repaired that section)?

Next, two sets of trailer lights that were both hacked in (one set by me a few years ago and the other by my dad who knows when), I had previously just clipped them and shoved them in the quarters, so a bunch of + wires bouncing around in there. Not great. Removed all traces of trailer wiring and made repairs to the wires were they were spliced in.
Not sure if either of these findings are relevant but they couldn’t be helping.

Here’s another find: the power wire for the fuel pump (red with green stripe) was melted in its connector, and had a strange splice in it about an inch from from the body-side connector. Not sure what the story is here but I’m sure there’s a connection between the floating ground with the tailights and why the Circuit Opening Relay clicks with the brakes. Like you said @FJACS

 

[cruisermatt]

Here’s my tailight harness alien abortion and the bundle of trailer light wiring I pulled.
I’m going to go pull a tailight harness of a parts FJ62 tomorrow.
I am really holding that is somehow the link between the lights and the starter, especially since there wasn’t anything under the dash that was immediately obvious.

On a side note,
I am now using these connectors that have a heat shrink insulator that are adhesive-lined for splice repairs. Here’s one on my tailight housing where the trailer lights were.

 

[FJACS]

Some of the trailer wiring boxes need a power supply. Perhaps your dad spliced into the fuel pump wiring to run a keyed power supply for the unit. Not a bad idea.

 

[cruisermatt]

I don't think so, all of the wires from the system he installed (last century probably) were accounted for. I've since made a new circuit for the fuel pump that's separate from the Toyota wiring (recommended for engine swaps by the way, the Toyota wiring is the opposite of overkill which is what you want), so its not a huge deal, I will repair it regardless as loose ends bother me.

 

[cruisermatt]

I was luckily able to acquire a replacement tailight harness locally today thanks to @FL cruiser
I will get it installed tomorrow (with my heat shielding so I don’t melt it like the last one!)

Fingers crossed this is the issue or is at least majorly contributing to the issue.

 

[Randy88FJ62]

Wow, what a mess. Sounds like my early days playing with wiring when I bought my truck.

Years ago I was driving down the highway and the tires I bought the truck with were old. The rear driver's tire blew and ripped out the fuel pump wires. I had to splice them on the side of the road. The only reason I knew what I was looking at was I had swapped the fuel pump about a year prior.

Glad you are getting close to a solution. Sounds like factory wiring wasn't the problem but the people touching it after

 

[cruisermatt]

Glad you are getting close to a solution. Sounds like factory wiring wasn't the problem but the people touching it after

Yeah, that’s what’s it’s looking like more and more. I was just hoping it wasn’t something that I was the cause of, on the bright side though it’s looking more and more like everything under the dash is fine which would be great.

 

[cruisermatt]

Here’s the “new” used tailight harness. Going out to install it in a few minutes. It also has those trailer lights spliced in but only on one side. I am going to remove those vampire clips and repair the wires since I never tow anything with this rig.