Hi/Lo range switch FG637

gait

Explorer
when I bought my 2nd hand FG649 there was a spare hi/lo cable in the cab. Explanation was the cables can chafe where they exit the cab and eventually gear can't be selected. I haven't seen the problem.
 

Aussie Iron

Explorer
Having usual problem with low range not wanting engage, any tips or pointers on where to start to diagnose/fix??

Thanks!

Need a bit more info. Is it a cable shift transfer case and you are having problems with the switch that works the dash lights (this is mounted on the transfer case) or it a vacuum shift and you are having trouble with the dash switch that operates the vacuum solenoid for the vacuum shifters on the transfer case.

Dan.
 

PilbaraFG637

New member
Need a bit more info. Is it a cable shift transfer case and you are having problems with the switch that works the dash lights (this is mounted on the transfer case) or it a vacuum shift and you are having trouble with the dash switch that operates the vacuum solenoid for the vacuum shifters on the transfer case.

Dan.

Its the vacuum shift with dash switch. Prev owner said it was working and only couple of weeks before putting it up for sale - made me aware of it before i bought it.

Is there a fuse for it anywhere, had quick inspection of vacuum hose when i bought it and seemed ok and just thought it may be an electrical switch/fuse fault?
 

kerry

Expedition Leader
I'd use a Mity Vac to check vacuum status and even to see if you can shift it by manually producing vacuum. If the vacuum checks out, then it's likely electrical.
 

Aussie Iron

Explorer
Sorry but none of my manuals cover the vacuum shift so I would say you have to go back to basics. Check all fuses in fuse box in the centre of dash. Relays are behind glove box. I would find the solenoid units and check for current there first. Pull the switch out of the dash and check it, check for power at switch. I would believe the switch operates a relay to send power to solenoids. Chances are there are two relays - one for 4WD and one for High/Low.

Dan.
 

PilbaraFG637

New member
Just and update on issue, checked all fuses, relays and solenoids and nothing was found to be an issue, just switch on dash didnt receive power. Traced power wire as far as i could but ties back into main harness and could have shorted or broken anywhere through the harness.

So just used power wire from the oil level check switch next to it and voila! it works!
 

JohnRogers

Observer
On my NPS i had 2 issues first was broken vacuum lines to diaphragm on transfer case replaced them checked activation by sucking on lines, all good! But still no activation spent hrs tracing wiring loom looking for broken wire due to no power getting to solenoid all good till i found little black box up under dash board called "4WD control module" that isnt mentioned in any manual but when you give part number to Stealership, turns out $275 fixes the problem.
 

SkiFreak

Crazy Person
turns out $275 fixes the problem.

Be thankful that you don't have a Fuso, as that part would have probably cost you double that.
I do like my Fuso, but the price for spares is ridiculous, compared to similar parts on an Isuzu. Sigh............
 

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