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'02 4x4 Trouble

2K views 11 replies 6 participants last post by  simonsays 
#1 ·
I have found other threads with 4x4 trouble but not quite like mine. I was use the 4x4 (auto) on and off while backing up a trailer on loose ground when it just quit working. No light no nothing. I checked to see if it was engaging the t-case at all and it is not. What are the issues that can happen between the switch and t-case motor/shifter? Is it usually aN electrical problem or does the motor/shifter just give up?

THANK YOU IN ADVANCE!
 
#3 ·
Did some checking and found this:

Under the hood by the firewall/drivers fender, there are a couple of boxes big enough to hold two relays each. Open the one that is closest to the fender and swap the two relays around see if that makes the 4x4 come on.
If this doesnt work its either wiring or the gem module. Not sure what years have it. I was told my 2002 doesnt have one.
 
#4 ·
I have to jump mine at those relays to get it into 4wd. The relay closest to the firewall is the 4x4 hi and the relay closest to the front bumper is the 4x4 low. Pin 30 (closest to the engine) on each relay you have to give 12v. But you have to just tap it and check each time otherwise the motor will go too far.

So it you are stuck in 4x4 low, you need to give pin 30 on the 4x4 hi relay 12 v for 2 seconds. That would put my truck in 2wd. Hope that helps.
 
#5 ·
ok so i got mine figured out so here we go dont make my mistake and do testing first lol then tear apart but go in the engine compartment and pull the two relays that imcummin mentioned and check the spade holes on both that face the firewall and the ones facing the front of the trucks (sorry forgot to right the spade numbers) with the key off take a volt ohm meter and check all four of the holes i told you (same two holes on both relays) you should be reading somewhere around battery voltage but it should be at a minimum of 9 volts if any one of them is not 9volt + you need to check for a broken or corroded wire. if they all read more than 9 volts then ohm the center spade and that should read no more than 8 ohms if it does you need to check those wires. what happened to mine was the backside of the relay harness (which is covered by a black harness cover with two clips) was corroded on the relay closest to the firewall on the spade closest to the firewall which caused the wire to break so i had to remove the clip inside the relay plug get a new one wire it in and reattach it into the block then clear the codes. however it still looked like i was stuck in 4 wheel low but you have to put the truck in neutral and step on the brake then switch the 4x4 switch to 4 hi or 2wd then it will function properly try this and if it doesnt help or you need further instruction let me know and i will procede down the flow chart Tyler (i also posted that in my thread but thought it more important since you had some responses in your thread)
 
#9 ·
I have heard of the motor that engages the trans case going bad . Seems to be quit common too .
 
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