So here I am on vacation, and what did I just do? A completely non-essential modification to the Land Cruiser. But sometimes there’s nothing more satisfying than a quick fix or mod that you do not because you have to, but because you just want to.
’91-’97 Toyota FZJ80 Land Cruisers are equipped with all-time all-wheel-drive, but have quite a few options for locking the differentials. While all have the ability to lock the center differential, on the ‘91s and ‘92s this is done manually through pressing a CDL button on the dash that can be punched whether you’re in 4High or 4Low, whereas the ‘93s and later lock the center diff for you automatically when you shift into 4Low, and don’t let you lock it in 4High.
In addition to the center differential locking, some FZJ80s have an optional side-to-side locking package, a knob left and below the steering wheel that can be used to lock the rear diff, then the front. Mine doesn’t have this, and it’s a ’93 so the center diff is only locked in 4Low.
Make no mistake, driving the 1/8 mile on sand out to Surfside Beach isn’t rock-crawling in Moab; you don’t need any fancy locking. And, let’s face it, one of the nice things about all-time all-wheel-drive is that it’s exactly that – on all the time; you don’t need to remember to turn it on when you hit the sand. Most of us who have taken vehicles onto sand, if we’re honest, will admit to getting stuck at least once because we thought we were in four wheel drive but weren’t. But, I thought, it would be nice, on some of those softer, ruttier sections on the six-mile run out to Great Point, to be able to leave the TLC in 4High and lock up the center differential.
There’s a trivial mod I read about on www.ih8mud.com (the Land Cruiser enthusiast web site, and the name is a joke – it should be iheartmud) that lets you do exactly this. It turns out that when Toyota deleted the CDL switch in ’93, they left the wiring harness and connector in place, so you simply fish the connector out from behind the dash and install an OEM dashboard switch from a ’91 or ’92 (or even pilfer the hazard switch; the pinouts are the same). I’d actually bought a CDL switch prior to going on vacation last year, but never got around to the installation.
So this morning I thought I’d take a stab at it. The Slee Off-Road web site has a detailed DIY showing exactly which dashboard screws need to be removed to pull the dash plate and access the dangling bit of wiring harness with the connector on it. Sure enough, in about 20 minutes, I had the switch plugged in. I pushed it, expecting to see the center lock and ABS indicator lights on the dashboard (the ABS being disabled during center diff lock).
And of course, I saw… nothing.
More reading on ih8mud unearthed multiple threads on the “I hit the CDL switch and nothing happens” problem. The most common problem seems to be that so many of these trucks were never taken off road and never put into 4Low, so the center differential was never locked, so the actuator motor sticks. Don’t panic, the advice was – lock and unlock the center diff a hundred times, either with the newly-installed switch or by moving the mechanical lever between 4High and 4Low, and it should unstuck. I tried this, but still the lights never came on.
I found a wonderfully thorough troubleshooting guide for the CDL on the Pacific Northwest Backroad Adventures web site (http://www.pnwadventures.com/vehicles/toyota-fj80-landcruiser-cdl-troubleshooting/, if you need to see it). I tried to suck it and all its photos and illustrations through the dial-up (yes, dial-up) internet connection that I have here at the rental house. Not all of the pictures came through, but the troubleshooting text did. In addition to ih8mud’s lock-and-unlock-a-hundred-times advice, the pnwadventures guide made the point that it’s possible that the truck’s center differential is, in fact, locking, and that all that’s wrong is that the dashboard lights aren’t coming on.
First I did the easy things. I made sure that the newly-installed CDL dashboard switch worked by pushing it in and out and verifying the clicking of the transmission relay. Then I pushed in the switch and drove the car in tight circles and verified that I did not feel the skitching of the wheels or the decreased turning radius one would expect if the center diff was actually locked. Then I made sure the dashboard indicator lights worked by pulling the connector off the CDL confirmation indicator switch on the center diff (where a rod inside the center diff pushes against a detent – just like a reverse light switch) and jumpering across the harness side of the connector with a paper clip. The CDL and ABS lights came on, so there was nothing wrong with the indicator lights themselves.
Unfortunately, this was pointing to a bad actuator motor. I tried to follow the guide and troubleshoot the actuator motor itself. There’s a nifty trick you can do by applying voltage from a 9V battery and listening for the motor. I tried it and didn’t hear anything. Continuing to dutifully follow the guide, I checked the resistance between certain pairs of pins on the actuator connector, and in the harsh binary language of troubleshooting matrices, everything was reading “Actuator bad. Replace.”
Damn, I thought this was going to be easy.
There was one more test I needed to do – verify that voltage was getting to the actuator motor – though if the actuator was bad, this was a moot point. But I inserted the probes of the voltmeter into the actuator motor connector, pulled the voltmeter out to the side of the truck where I could see it, leaned inside the truck, and hit the switch. The voltmeter read zero.
But, with my head down low so I could read the voltmeter… what was this whirring sound I was hearing? I hit the switch again. Whir. Again. Whir. Again. Nothing. Again. Whir. Again. Nothing.
I called my niece Guthrie over and asked her to sit in the car and hit the switch every five seconds while I was underneath listening. It turned out the actuator motor was working, though intermittently. This explained why I didn’t feel the center diff was locked when I drove in a tight circle – it was probably during one of the intermittent cycles when it wasn’t engaged. The other troubleshooting anomalies were due to the fact that I was testing at the wrong connections because my dial-up internet didn’t have the bandwidth to download the pictures.
The only question remaining was… why weren’t the dashboard indicator lights coming on? Posts on ih8mud indicated that the CDL indicator switch on the center diff does, in fact, go bad. You need a 27mm wrench to pull it off. You can test it and try to clean it, posts said, but it probably just needs to be replaced. I looked in the tools I’d brought to Nantucket, and incredibly, I actually had a 27mm ½” socket. I crawled back beneath the car, but there wasn’t enough clearance to get a socket and a ½” ratchet over the switch.
Ok, I thought. That’s that. The CDL actually is working, though intermittently. The main issue is only a lack of confirmation from lack of indicator lights. I can’t get this switch out, and even if I did I don’t have a replacement. And I don’t need to be doing this anyway. We’re done.
I came back inside and was about to wash up when I thought… I wonder if I can reach that switch and get it out with the Vice Grips?
As trivial a problem as this was, if anything is bedrock for the whole Hack Mechanic ethos, it is this. Not giving up. Not walking away. Trying it again. Trying it from a different angle. Using a different tool.
I crawled under with the Vice Grips, tried a few angles to grab the switch, and out it came. I tested its continuity with the voltmeter, and it was bad. I thought better just put it back in don’t want to take the truck “down” when everyone is going to want to go the beach in an hour. But, again, hell, I was holding the damned thing right in my hand; why not give it five minutes of my attention?
I thought, if the CDL hadn’t been exercised in many years, neither had this switch. I pushed it in and out a hundred times, retested it with the voltmeter, and it now was working. I reinstalled it, put the plug back on it, turned the ignition key on, hit my newly-installed CDL button, and the CDL and ABS indicators on the dash immediately glowed. I hit the switch again and they went out.
It’s not going to matter in terms of getting out to Great Point and back, but it was a great way to spend a vacation Sunday morning.