Melted relay block help

[atm0706]

Hi,

I'm the unfortunate new owner of a triple locked 1994 Land Cruiser with some electrical gremlins. I bought it on eBay as it was listed as a strong running truck, and the owner sent me lots of pics and videos of it driving. Unfortunately, when it arrived it would crank but wouldn't start and had to be winched off the transport truck and towed home. He conveniently left out all of the bad stuff from the photos i received and there's some issues. eBay is unwilling to help me out in any way, and the seller claims it ran and drove great when it left his possession. Basically, kick rocks.

When I got it home I started poking around trying to figure out why it wouldn't start and found that the fuse block on the left fender was melted at some point and still has live exposed wires in it. At some point, a previous owner jankily ran wires from the battery to the ignition coil with a relay in between. some of the wires were disconnected from the relay when i got it, and the wire going from the positive battery terminal appears to have been cut. I also noticed that with the key in the accessory position, and when cranking, theres no check engine light on. I'm not very experienced with wiring on cars, and don't really know where to start with getting this fixed besides for just replacing the harness which is going to be a big undertaking, but seems to be the best option. I found a wiring diagram for the 94 on the forum and have been looking at it, and it seems that I will need to replace the whole front engine bay harness? I found one for sale at Cruiser Yard, but its a lot of money and I don't want to buy it until I'm sure its what I need. I am open to other suggestions as well if anyone here with more experience and insight may know how to fix this. I paid more than i should have for this truck based on how it arrived to me, and cant afford to be throwing money at it to get it to run when it was supposed to already. I budgeted for basic maintenance, not this.

I've attached some pictures of the fuse block and the janky ignition coil wiring.

 

[StuCruiser]

impossible to tell from the photos, sorry.
Do you have a wiring diagram for your truck? You’re going to have to follow that and make sure you have every wire in it’s correct location, starting from the battery and working through the complete starting circuit.

 

[NeverFinis]

owner sent me lots of pics and videos of it driving.

Any of those pictures include the engine bay?

Your charge fuse should only be 7.5, not 15. The fuse block cover should have the correct fuse sizes.

The fuse that melted is the EFI Fuse. My guess is that the external relay was replacing the EFI relay.

I would ask in the classified for the driver's side loom, but I would attempt to fix what you have first.

If you have the skills, the fender fuse block can be opened, and the wiring can be fixed.

With an 80 series, you either need money, or skills. After your purchase, you appear to lack the first, so work on the second.

 

[MissahPapaJ]

With an 80 series, you either need money, or skills. After your purchase, you appear to lack the first, so work on the second.

I’d say with a 80 series it’s best to have money and skills if you don’t want to get ruined financially, boy there’s nothing like getting a 80 series that has had next to no upkeep or years of questionable work done to it. I get 20% off of OE parts through my shop and I still spent well over 800-1000 in parts getting the cooling system dialed and vacuum / PCV refreshed and I did all the work myself which took about 12 hours to do although some time was just spent cleaning parts up.

 

[jht3]

not sure why you posted a pic of your a/c compressor? other than some odd wiring/grounds going on.

it all looks fixable, based on what i see. go to the resources section on this site, and get a copy of the EWD. you DO have a digital multi meter, yes?

you can de-pin your fuse box and replace it (if you can find one cut from a parts truck. i don't think you can buy it standalone). fixing any burnt wires and replacing the connectors that were cut off. you can buy pre-terminated pigtails straight from toyota. there is another wire repair manual in Resources, which can help determine part numbers.

the melted location is the EFI fuse. should be a 15A fuse there. the white and red/yellow wires poking out should connect to the fuse. the R/Y feeds the EFI relay, which is still in your fuse box, but likely not doing anything? the EFI relay does important stuff, like power your fuel pump relay.

i'd check your wiring at the fusible links. especially the vehicle side. and replace the links. common for those to go bad, with janky repairs.

none of that green wire is stock, as far as i can tell. i can't tell from your pics where it all goes. my first thought was someone rigged up a hotwire to the starter. lots of our trucks have issues starting due to wiring issues through the ignition switch and neutral safety switch. but since yours cranks, that's working at least.

 

[Dragos80]

Easy fix I am sure.
I think the starter is bad and he wired it using a relay.
If that is the case you need to rewire everything correctly.

I will post a link in a few moments.
Again, assuming that's what it is. Still difficult to diagnose from the pictures.

 

[Dragos80]

Most of the time the starter solenoid goes bad. For some reason replacing the starter does not cure the problem in most cases.

Anyway, if this is the issue with your truck (the wires on your truck might have become loose and no long provide the necessary contact and power to your starter... maybe).



Fusible Link replaced, no CEL still difficult to start, delayed crank - https://forum.ih8mud.com/threads/fusible-link-replaced-no-cel-still-difficult-to-start-delayed-crank.1372442/

 

[Brindleboxer]

I would also suggest reaching out to some of the guys that part out vehicles and see if they have the parts you need. You of course will need to know what is bad and/or needs replacing first unless you just shoot the whole harness assembly at your truck. @slow95z, @Deathvalleypaul and @swamp-thing are some that come to mind.

 

[slow95z]

so since i got tagged i will chime in with something i have seen in the past.

the 93 and 94s are known to have bad wiring for the starter and running another wire on a relay is an easy fix. i have done it myself on 3 different ones and it works great. maybe thats what is going on there its just done poorly.

 

[swamp-thing]

i can help you out with just about any replacement part you want, just message me directly if you get to that point, as others have already mentioned, top priority finding the source of the isse — fix — then swapping in a clean block would be best..

 

[atm0706]

Thanks to everyone who replied. I’m relatively mechanically skilled and have other modified cars, but I’m not an expert, especially when it comes to wiring/electrical stuff. Even more so when I’m trying to figure someone’s janky repair.

The starter works great and cranks the engine over just fine. It just won’t fire and start.

A/c compressor picture was an accident. I got carried away selecting the photos to upload. But it shows more bad wiring lol.

The janky green wiring appears to be running from the battery to the the ignition coil with a relay, but the relay wasn’t even completely hooked up and the wire they ran to the positive terminal was cut when I got the truck so not sure if that was even doing anything to begin with.

I did get pictures of the engine bay, but not super detailed ones and I couldn’t see any of the green wiring because it was all tucked behind the battery tray. The fuse box had the cover on it so I couldn’t see that either.

I did get the wiring diagram, and I’m going to try and connect the white wire to the red/yellow wire in the fuse box and see if it starts. Should I get a fuse holder first? Or is it okay just to connect the together temporarily to see if it starts first? I did notice that the EFI relay does click when I touch it while someone else cranks the engine over.

I don’t have a check engine light at any point though, som I’m thinking the ecu isn’t getting power to fire the igniter. Someone elsewhere told me that the ecu controls the igniter and even if the coil and distributor have 12v, it won’t fire if the igniter isn’t told to do so by the ecu. I’m hoping the melted efi fuse location is the issue and fixing that allows it to start.

 

[atm0706]

i can help you out with just about any replacement part you want, just message me directly if you get to that point, as others have already mentioned, top priority finding the source of the isse — fix — then swapping in a clean block would be best..

Do you happen to have the fuse relay block for the 93/94 that I need? I found one on eBay for $100, but the seller wants like $75 to ship it.

 

[Brindleboxer]

Pull up the EWD for the truck and trace where the wires from the battery go, the fusible link wires. There are three and from your pictures I cannot see any of them. The "home brew" wiring may be in lieu of them but you may be missing some connections. I do notice your engine ground on that side looks like it is still intact (that's good).

There are some recent posts with the crank no start albeit not exactly what you are describing but the methods for finding the problem all route back to the core principles.

Post in thread 'HELP 1994 Toyota Land Cruiser Crank/ no start'

Oct 6, 2026

Here are a couple recent posts with a "crank, no start". The first post also has a quick link to the FAQ for a vehicle that won't start and procedures to narrow your search for the culprit.

I would also suggest downloading the FSM and EWD from the Resources section as they are invaluable.

• Brindleboxer

• 

 

[atm0706]

I did a bit more research and poked around on the car today and I think I found the cause of the melted EFI fuse location. I read that the o2 sensors are common causes of a short, and sure enough both of them have also had the hack-job treatment done to them.

One of them (the outside one) was easy to fix by undoing the crappy twisted together wires and electrical tape and using butt connectors. Probably not ideal, but its better than it was before. They had the shielded signal wire wadded together with the shielding too, so i separated them, soldered and heat shrinked the signal wire, and then soldered the shielding wire back together separately.

The other one is going to be a doozy i think. They had two of the four wires running underneath the engine to the driver side and back up that side, and the other two running up the side of the transmission/engine n the passenger side over the bellhousing and back to the driver side. They appear to be going into a loom under the intake manifold near the starter. It seems like the only way to reach them to fix it is to remove the intake manifold. Is that correct? I havent check back to the wiring diagram yet to see where they run. They are a mess though. Twisted together in like three places, no electrical tape or sheiling, just resting on the bare metal of the engine in a few places. and they were also draped over the drive shaft as well... at least that section had corrugated loom "protecting" it . I've attached a few pictures but it was hard to capture and they probably wont really help anyone help me. I basically need to figure out where that o2 sensor connects back to the harness so I can fix the wires or run new ones in a more intelligent way.

This is a bad picture of two of the wires running back up the passenger side of the engine after crossing underneath it.

This shows (from the top) the wires running from the o2 sensor plug and splitting around both sides of the engine.

this is where the appear to meet back up with the main harness, in this corrugated loom, though I'm not completely certain yet. Its under the intake manifold just above the starter. does that seem correct for where the o2 sensor wires run back to from the plug?

the repair on the easy sensors wires that I did. It was much worse before. Just loosely twisted and taped together. Signal and sheiling of teh larger blue wires was all twisted together not searated.

 

[atm0706]

Cant seem to figure out how to edit my last post, but i basically want to fix all this o2 sensor wiring before i attempt to connect the two EFI fuse wires with a fuse and try to start it. I'm pretty sure this is what caused it all to short out and melt in the first place, but I'm not certain of that yet. Really hoping that after this it'll be fixed though. I found a fuse block and purchased it, so hopefully Ill have this o2 nonsense sorted out by the time it gets here.

 

[mudgudgeon]

Should I get a fuse holder first? Or is it okay just to connect the together temporarily to see if it starts first?

Until you know what caused the fuse box and fuse to melt, absolutely essential to use a fuse. You can temporarily rig a fuse holder in for testing

With the wiring diagram, figure out what draws power through that fuse.
Fuel pump relay was mentioned. If the fuel pump has a short circuit in it, maybe it's pulling too much current. Or maybe there's a damaged wire that's shorting to ground and pulling a lot of current.

If you connect these circuits up without a fuse, and you haven't found the root cause of the melted fuse, you risk burning up wiring harness, and potentially causing a fire that could cost you the entire truck

 

[atm0706]

Until you know what caused the fuse box and fuse to melt, absolutely essential to use a fuse. You can temporarily rig a fuse holder in for testing

With the wiring diagram, figure out what draws power through that fuse.
Fuel pump relay was mentioned. If the fuel pump has a short circuit in it, maybe it's pulling too much current. Or maybe there's a damaged wire that's shorting to ground and pulling a lot of current.

If you connect these circuits up without a fuse, and you haven't found the root cause of the melted fuse, you risk burning up wiring harness, and potentially causing a fire that could cost you the entire truck

yes, i believe i found the cause of the short to be coming from the o2 sensor wiring like i showed in my last post. I fixed on of them, but fixing the other one is going to be a challenge. It looks like ill need to remove the intake manifold, unless someone here with more knowledge and experience has a better idea. It looks like the wiring from what i can see in person and on the wiring diagram runs back to the main harness on the driver side right underneath the inatke manifold. I cant reach my hand in the really, let alone repair the wires.

 

[mudgudgeon]

yes, i believe i found the cause of the short to be coming from the o2 sensor wiring like i showed in my last post. I fixed on of them, but fixing the other one is going to be a challenge. It looks like ill need to remove the intake manifold, unless someone here with more knowledge and experience has a better idea. It looks like the wiring from what i can see in person and on the wiring diagram runs back to the main harness on the driver side right underneath the inatke manifold. I cant reach my hand in the really, let alone repair the wires.

Yeah, I posted before I read to the end. Looks like a good start.

Based on the quality of repairs by the PO, stay suspicious of other potential issues.

 

[jht3]

The Yellow-Red wire side of the EFI fuse feeds many critical circuits, all detailed in the EWD. they include

• circuit opening relay
• data link connector 1
• ECM
• fuel pump relay
• fuel pump resistor
• fuel sender and pump
• o2 sensor 1
• o2 sensor 2
• idle air control valve
• MAF
• VSV (EGR)
• VSV (fuel pressure control)
• EFI main relay

you've found suspect wiring on the o2's. trace the other circuits and see what you find.

have you inspected all the fusible links? any funny business going on there? could be the source of your check engine light, or lack thereof

i suspect someone was blowing EFI fuses, and kept putting in a higher amp fuse, or even a metal jumper, until the fuse box and wires melted

 

[atm0706]

i havent removed the fuse block to check the wire, or traced it to any other components yet. I first want to tackle this o2 sensor wiring since i know its messed up. I just need to figure out how to do it first without taking apart the entire intake manifold assembly. seems like i'm going to have to though.