Crap

[whyzee125]

Hey guys,

So I just realized I have an issue and it's unfortunately worse than I at first thought.

I have a 98 5 speed with e locker and the 4wd light does not illuminate when in 4wd. A little research pointed to the front differential ADD switch as the likely culprit. I swapped it out with my other 4runner, which was confirmed good, and the problem was still there.

The 4wd works perfectly in high and low, just no light. If i try to activate the rear locker, the 4wd light then starts blinking, stating that I need to put it in 4wd to engage the locker.

I looked at the wiring and found the issue. The big wiring harness that has plugs in the trans, transfer case, etc. and goes to the fusebox was not attached to the bell housing bolt like it should be and was touching the manifold. The harness actually for the most part looks fine but right at the top the sheath is melted through so I'm guessing the wires just to the ADD switch got melted.

What's the best way to fix this? Access is VERY limited in there but I want all my ish't to work properly.

Thank you!

 

[brillo_76]

Man that is a really tight spot to get into. Best to remove the outer sheath in that area that is melted. Separate and verify all the wires are intact. Use liquid electrical tape on each wire that isolation is damaged to reseal the individual wires then if possible, use electrical tape over where that sheath that you cut and removed to reseal that area again. Because of that location its a PITA to get in there and its a pain to completely disconnect that harness with everything in there. Mostly those old seam rippers that sewing people use will work great for removing the damaged sheath unless its really melted to the wires.

 

[whyzee125]

Man that is a really tight spot to get into. Best to remove the outer sheath in that area that is melted. Separate and verify all the wires are intact. Use liquid electrical tape on each wire that isolation is damaged to reseal the individual wires then if possible, use electrical tape over where that sheath that you cut and removed to reseal that area again. Because of that location its a PITA to get in there and its a pain to completely disconnect that harness with everything in there. Mostly those old seam rippers that sewing people use will work great for removing the damaged sheath unless its really melted to the wires.

Thank you, Brillo. I can always count on you knowing exactly what's going on! I'll try to get under there and better assess the damage today. I don't believe ther'es a lot of damage to the harness as there have been zero other symptoms but I want to stop it before it gets worse. Glad i caught it before the whole thign melted!

 

[brillo_76]

Yes the idea is to just seal the wires good. Worst case you can fix the outer loom on the next clutch replacement with the transmission out of the way and the wiring all disconnected from the transmission and the transfer. provided the wires are sealed up again.

 

[whyzee125]

Yes the idea is to just seal the wires good. Worst case you can fix the outer loom on the next clutch replacement with the transmission out of the way and the wiring all disconnected from the transmission and the transfer. provided the wires are sealed up again.

Well I actually don't know what to think now. I was about to cut it open then realized it's really just a slight bit charred but it's on the heat foil. It sure seems like the inner wiring would be fine based on the close up condition of the whole harness.

Checked the front diff switch, both t case ones, all fuses, and even did the gray wire mod. Absolutely nothing will allow the damn locker to engage or the 4x4 light to come on but the 4x4 light does blink when you try to engage the locker, as if the truck doesn't realize it's in 4wd. the gray wire mod should override this but it isn't and the 4wd is still working just fine. I'm honestly getting fed up with these trucks.

 

[brillo_76]

You have any photos? It maybe alright. I have seen the vacuum relays(ADD) fail on one of mine. It wouldn't enable the front diff.. Turned out the relays just failed. (Mugged bogged in its past.. ;( ) You can check those relays though and verify voltage is going to them.

Is it just not enabling the front diff? I know the light isn't coming on. I have one of those too in a rig. The light is iffy but the 4wd works so I wasn't majorly concerned about that issue.. I may get to the switch someday on that one.


You can jack up the rig, put it on 4 jack stands to verify if the ADD system is working. The jack stands will let you thoroughly test things safely.

 

[whyzee125]

You have any photos? It maybe alright. I have seen the vacuum relays(ADD) fail on one of mine. It wouldn't enable the front diff.. Turned out the relays just failed. (Mugged bogged in its past.. ;( ) You can check those relays though and verify voltage is going to them.

Is it just not enabling the front diff? I know the light isn't coming on. I have one of those too in a rig. The light is iffy but the 4wd works so I wasn't majorly concerned about that issue.. I may get to the switch someday on that one.


You can jack up the rig, put it on 4 jack stands to verify if the ADD system is working. The jack stands will let you thoroughly test things safely.

Thanks for the reply! I'm fairly certain it's not vacuum related as the 4x4 works perfectly but the light won't come on. That's not the end of the world but it won't allow the locker to engage either as it starts flashing the 4x4 light when I try, even with the grey wire mod so I have no locker because of whatever's causing it

 

[whyzee125]

You have any photos? It maybe alright. I have seen the vacuum relays(ADD) fail on one of mine. It wouldn't enable the front diff.. Turned out the relays just failed. (Mugged bogged in its past.. ;( ) You can check those relays though and verify voltage is going to them.

Is it just not enabling the front diff? I know the light isn't coming on. I have one of those too in a rig. The light is iffy but the 4wd works so I wasn't majorly concerned about that issue.. I may get to the switch someday on that one.


You can jack up the rig, put it on 4 jack stands to verify if the ADD system is working. The jack stands will let you thoroughly test things safely.

I'll get a picture in the morning for you! I think it almost has to be the harness unfortunately

 

[NegroTundra]

I had this problem, also on a 98 5 speed. The j-shift selector, when I would shift to 4wd, was not activating the solenoid switch. I removed that switch from beneath the shifter, cleaned it up on my workbench, reinstalled and voila.

Perhaps that may be it for you as well?

 

[whyzee125]

Thank you for the reply!

Well it ended up being neither--I took it in and there was a solder joint on the back of the gauge cluster circuit board that had burned out. They re soldered it and the light works perfectly.

Now the annoying part is the locker light still just blinks, even in 4 lo. I don't hear it trying to engage or anything. Ugh.

 

[BuffaloBass]

DANG! as i just finished an R&R, i was going to suggest unbolting the harness from the transmission, unplugging it from the trans an dtransfer case, or as much as is needed for the wiggle room necessary to repair any damaged wires.

 

[brillo_76]

I cant say i heard of a lot of bad solder joints in the 3rd gens. That's very interesting and good to hear your got it fixed up..

 

[whyzee125]

Thank you! Honestly it is super strange and I'm now realizing my locker has THREE separate issues, one of which may have caused the solder joint issue?

I still couldn't get my locker to engage so I pulled the motor/actuator off. It turned to crumbly concrete and the gear part was stuck inside the housing until I chipped it to pieces. It was completely seized and came off in about 100 pieces. Okay so got a good used actuator that works perfectly when hooked up to a battery.

Still nothing when on the truck. The wiring I initially suspected looks great, can't find any wiring issues or an issue with any of the connectors and the little black box inside the truck clicks when I push the button. Still absolutely nothing when on the truck.

I manually engaged it and now it (to match the position of the used motor) and it's now locked but doesn't realize it's locked and won't unengage. I'm so frustrated.

 

[brillo_76]

Thank you! Honestly it is super strange and I'm now realizing my locker has THREE separate issues, one of which may have caused the solder joint issue?

I still couldn't get my locker to engage so I pulled the motor/actuator off. It turned to crumbly concrete and the gear part was stuck inside the housing until I chipped it to pieces. It was completely seized and came off in about 100 pieces. Okay so got a good used actuator that works perfectly when hooked up to a battery.

Still nothing when on the truck. The wiring I initially suspected looks great, can't find any wiring issues or an issue with any of the connectors and the little black box inside the truck clicks when I push the button. Still absolutely nothing when on the truck.

I manually engaged it and now it (to match the position of the used motor) and it's now locked but doesn't realize it's locked and won't engage. I'm so frustrated.

Minor... Just pull the motor out and unlock it then put it back in. Anyways this makes a lot more sense. Amp or heat would cause loose solder joints. My guess, the motor was drawing just about the limit of the circuit and was heating up some joints. My guess is now you need to verify the wires are making the connection. Maybe a few more joints are loose too along the path.

The binding motor caused this high amp situation and the joint issue. If a dc motor is stalled it will draw a pile more current trying to work. Plus the starting amps is a lot higher then the running amperage.

 

[whyzee125]

Could these have anything to do with it? I pulled the panel above the drivers knees and there are 2 plugs that weren’t plugged in to anything and I don’t see anywhere they could go.

The left one is for the clutch start cancel. The top right is for the e locker and the one to the left of it is for the dimmer for the gauges.

The bottom right two don’t seem to go anywhere. Related?

https://imgur.com/a/kXwb1QN

 

[phattyduck]

Could these have anything to do with it? I pulled the panel above the drivers knees and there are 2 plugs that weren’t plugged in to anything and I don’t see anywhere they could go.

The left one is for the clutch start cancel. The top right is for the e locker and the one to the left of it is for the dimmer for the gauges.

The bottom right two don’t seem to go anywhere. Related?

https://imgur.com/a/kXwb1QN

Nope, normal. One is a (second) power mirror control connector. I always forget what the second one is for.

-Charlie

 

[whyzee125]

Well I ended up taking it in. Huge thanks to Brillo for sharing the diagram with me and it helped me narrow somethings down. I think it may be a bad 4x4 ecu bc it clicks when I push the button but no power comes out of it. The shop I took it to has a few 4runner nerds that work there and they have a few parts trucks so whatever it needs, they'll likely have a used one on hand they can sell me.

 

[whyzee125]

Well now the shop is stumped too. The ECU is not sending power out but it is receiving power in. They swapped it with a known good one out of a truck with a working locker and the "new" ECU does the same thing in my truck as the old one does. My ECU works in that truck too. All wiring is testing okay so far and now the gauge cluster issue has returned even though it has a working actuator.

 

[brillo_76]

Well now the shop is stumped too. The ECU is not sending power out but it is receiving power in. They swapped it with a known good one out of a truck with a working locker and the "new" ECU does the same thing in my truck as the old one does. My ECU works in that truck too. All wiring is testing okay so far and now the gauge cluster issue has returned even though it has a working actuator.

Extremely rare for it to be an ECU. So the wiring to the locker good from the ECU to the Acutaor? You ruled out the ECU. That only leaved a handful of things left. A few switches abs ecu and the limit switch in the rear locker itself.


If abs is working and the speedometer is.. That half rule out the abs ecu and cluster side of things.

What does that wiring look like going to the switch in the rear locker ?

M1(LG-R) and M2(LG) come from the locker ecu to engage the actuator with 2 more wires RLY1 () and RLY2 () The other wire to the Locker ecu is the power feed (B-W) wich goes to the 40 AMP 4wd Fuse.

Those 4 wires and the Ground wire (W-B) need to be verified they are not broken and are intact along with that switch on the locker as well.

If the ground wire (W-B) not intact. It will not work either.

 

[whyzee125]

Interesting you mention the ABS working properly. It does, I believe, but about once ever 2-3 months I'll get an ABS light for one drive cycle. I never worried about it, but if it's related, that would be awesome!

Supposedly the wiring all has continuity and looks visually good. Power applied at any junction causes the actuator to move but never if it goes through either ECU.