4WD Light Blowing Gauge Fuse (1 Viewer)

[CaptHamster]

Having a weird issue. 1990 FJ62, recently replaced a couple switches on the transfer case, one being the 4WD indicator switch that controls the 4WD light. 4WD is now working well, but I'm having an issue where the 4WD light coming on is blowing the 7.5A fuse that controls the gauges and the HVAC blower. It's fairly intermittent though, sometimes it will take up to 5 minutes of being on to blow the fuse, sometimes it's immediate.

Now though, when I run the truck and stop the engine, the 4WD light comes on for approximately 3-4 seconds after the engine stops. I then hear a relay or something click on the passenger side of the truck, and then the light goes out. I'm not sure if maybe I crossed wires somewhere, or if it's a short, or a bad switch? I'm utterly confused and would just like to use my 4WD without losing my gauges and A/C fan. Anyone have any ideas?

 

[Output Shaft]

You may have a "floating ground".
Make sure that the transfer case is grounded well to the body. There should be a wire connected to it attached to the body. Remove the wire, clean up the contacts and re-attach.

 

[CaptHamster]

Will definitely check that, thanks. Any idea as to what's causing the light to come on after shutting off the engine? Has something to do with a relay but I can't quite tell what.

 

[Output Shaft]

No idea as to why that light is coming on after shut down.
But whatever is supposed to come on after shutdown, it is using that 4WD indicator's path to ground. My guess is there is a bad ground somewhere.

When weird electrical issues arise on the cruiser, for example, the wrong indicator light coming on when something is turned on, or something else turns on that's not supposed to when some switch is flipped, that is usually an indication of a floating ground. The 60 series have ground junctions inside the cabin that lead multiple grounds wires to a common grounding doo dad, which then leads to a body ground. Sometimes the doo dad can get fried and the path to body ground gets compromised. (ie resistance). When this happens, the electricity finds the next best ground, and sometimes that might be through a motor, indicator light, or whatnot.

The wiring in the 60 series is definitely not one of it's attributes that earned the vehicle it's "Legendary" status.

 

[CaptHamster]

I agree, 60 series wiring is definitely not Land Cruiser tough (or necessarily simple). Good call on the ground wire, it was covered in mud and the contact was filthy at the body. Cleaned both ends of the ground wire and now my 4WD indicator switch from the transfer case is not working. 4WD itself works, but no light on the dash. Wondering if maybe the switch itself was shorted and cleaning the grounds just killed the switch? It's relatively new so I'd hate to have to buy another one.

 

[dpr64]

Did you ever find the cause of this or fix it? I am having an issue with all dash and hvac fuse blowing whenever I put it into 4low. I have not 4WD light at all and it appears to not be engaging into 4wd at all.

 

[CaptHamster]

No resolution to this quite yet. I am now having the added issue of my AT P light (above the auto shifter) lighting intermittently in 4H, N and 4LO positions of the transfer case. I also do not have any more 4WD light, but I know for sure my 4WD is engaged and working. I am wondering if the other two switches that connect to the transfer case are somehow shorting the 4WD light switch which is then blowing the fuse...I'm on the verge of just buying three new switches while I'm down there and seeing if that fixes it.

As to your issue of 4WD engaging or not, when you push the button or shift the transfer case (with the hubs locked) drive for a short distance then stop, get out and underneath the truck, and try turning the front driveshaft by hand. If it's loose or you are able to turn it, then 4WD is not engaged, which is likely caused by a faulty vacuum solenoid in the engine bay. If it is locked or you are unable to turn it by hand, then your 4WD is working.

 

[demimoore88]

Having a weird issue. 1990 FJ62, recently replaced a couple switches on the transfer case, one being the 4WD indicator switch that controls the 4WD light. 4WD is now working well, but I'm having an issue where the 4WD light coming on is blowing the 7.5A fuse that controls the gauges and the HVAC blower. It's fairly intermittent though, sometimes it will take up to 5 minutes of being on to blow the fuse, sometimes it's immediate.

Now though, when I run the truck and stop the engine, the 4WD light comes on for approximately 3-4 seconds after the engine stops. I then hear a relay or something click on the passenger side of the truck, and then the light goes out. I'm not sure if maybe I crossed wires somewhere, or if it's a short, or a bad switch? I'm utterly confused and would just like to use my 4WD without losing my gauges and A/C fan. Anyone have any ideas?

I'm having the exact same issue in my 88 FJ62. Wondering if you ever found a solution. Thanks!

 

[John McVicker]

Don’t have a clue if the 60’s and the 62’s are the same but I had the no 4wd light issue with my 60. Once I found the issue it was a 5 minute fix...and permanent.

The light connector wire was worn and shorting out. It’s on the ‘very’ top of the t case. As I remember...get on your back, get under the t case, reach up on the top of the t case with your right hand (the connection is on the top and passenger side), find the wire/connection and see if you have something loose or burned. If so, repair & you’re good.

Again, this was for my 60. 62 might not be the same.

 

[CaptHamster]

I'm having the exact same issue in my 88 FJ62. Wondering if you ever found a solution. Thanks!

I did find out, and it was pretty embarrassing. There is a bundle of wires (at least on mine there is) that includes all the transfer wires together that moves forward of the transfer case towards the engine. On mine, this bundle of wires had come loose from its hidey-hole and was dangling in the path of the front driveshaft. When 4WD was engaged, the wire bundle was knocking against the now moving DS and shorting the 4WD indicator light switch wire. I wrapped the bare wire in electrical tape, zip tied them all up and out of the way of any moving parts and all was good since then...

The 4WD light does still come on for a few seconds after engine shutoff. I think that happened when I swapped that 4WD bulb with an LED; probably a floating ground as OSS said, with just enough juice to light that low-voltage LED bulb.

Don’t have a clue if the 60’s and the 62’s are the same but I had the no 4wd light issue with my 60. Once I found the issue it was a 5 minute fix...and permanent.

The light connector wire was worn and shorting out. It’s on the ‘very’ top of the t case. As I remember...get on your back, get under the t case, reach up on the top of the t case with your right hand (the connection is on the top and passenger side), find the wire/connection and see if you have something loose or burned. If so, repair & you’re good.

Again, this was for my 60. 62 might not be the same.

Same on the FJ62, unless those wires come loose from the top of the t case and dangle down into the front DS...oops