fg637 low range

Tonkatuff

Adventurer
Hi

Help. I have a fg637 dual cab truck 2wd to 4wd changes no worries. But low range will not change from cab. I can manually actuate on tfer case and hanges and light comes on. The vacume works when I swap the 2wd 4wd hose it operates the lo range so the vacume is fine there is no voltage on the switch but I need advice or a wiring diagram
thanksk
 

whatcharterboat

Supporting Sponsor, Overland Certified OC0018
Hi Shannon,

Asked my mate Shawn who I was sure would have come across this before but he said all the 637's he had were converted over to cable shift . Apparently there was a conversion kit offered by FUSO for this or so he reckons. He used to change them all over cause the sand on the beach would play havoc with the vac activated setup.

I realise that probably isn't your problem and doesn't really help you much.....I doubt there is a speed lockout in the circuit but you will probably need to get hold of a wiring diagram to confirm....I'll ask someone else tomorrow who should know. I hope if any of the ExPo members have a diagram they might jump in. I would have thought that there was a fused power wire at the solenoid and the other side went to ground through the switch......if not then obviously the power goes through the switch and the solenoid is grounded close by with a black wire (possibly with coloured bands???) . What colours are the wires on the solenoid?

Will get back to you tomorrow if I can catch Michael. Wish I still had an old 637 manual on hand. Thanks
 

whatcharterboat

Supporting Sponsor, Overland Certified OC0018
Yeah no worries Shannon....I just spoke to my mate Michael again and he thought it was the same as I did.

"I doubt there is a speed lockout in the circuit but you will probably need to get hold of a wiring diagram.............. I would have thought that there was a fused power wire at the solenoid and the other side went to ground through the switch"

but really we are going to need to look at a diagram.......he said he's got one somewhere on his computer so I hope he can dig it up in a day or so......sorry. I was hoping someone here on the forum might have had one they could post up.......anyway, I'll try to follow up again.

Did you get a chance to look at the colour of the wires at the solenoid?? Also another place those things gave trouble was the main cab harness junction box ...follow the harness out of the cab and there should be a junction box so you can unplug all the wiring and remove the cab you'll find it probably on the left hand side in front of the radiator (in behind the grill) ....anyway sometimes they fill up with water and corrode the cable connections.....hey this is a long shot but that box is always worth a look if you can't find a gremlin. Match up the wire colour at the solenoid to the one in the harness at the junction box and probe it for power.

Will get back to you in a day or so unless someone posts up a diagram. John.
 
Last edited:

Tonkatuff

Adventurer
Just following up on this. I managed to get a service manual from member Kerry that is awesome but looks like all US FG637s were cable operated so still no further.

Sent from my RM-821_apac_australia_new_zealand_218 using Board Express
 

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