4 Low will not engage

[BoostedE21]

I dont know if you still have this vehicle, much less the problem, but in case somebody else comes across this thread, My explorer was exhibiting this problem and the problem was caused by the transfer case shift relay (located behind the radio)....I took the relay apart and noticed one of the circuits corroded completely into.....I jumped the circuit and 4 low worked perfectly....hope this is beneficial to someone.

Did you have to remove the radio to access the relay?

 

[96eb96]

Did you have to remove the radio to access the relay?

Yes, the relay is behind the radio. Check out this: 4x4 low diagnosis

If you hear no click, suspect a bad ground crimp at the firewall near the computer. You will see two black wires come out of a harness.

 

[BoostedE21]

Tha

Yes, the relay is behind the radio. Check out this: 4x4 low diagnosis

If you hear no click, suspect a bad ground crimp at the firewall near the computer. You will see two black wires come out of a harness.

That's really interesting......my Neutral Safety Switch is faulty (I can start in reverse/drive) - since the computer is looking for a combination of events to activate the relay, I wonder if that would cause the relay to not click on activating 4 low?

 

[96eb96]

Tha


That's really interesting......my Neutral Safety Switch is faulty (I can start in reverse/drive) - since the computer is looking for a combination of events to activate the relay, I wonder if that would cause the relay to not click on activating 4 low?

Possibly, that is why it must be diagnosed. You can test that switch by removing the GEM harness, putting an ohmmeter on the appropriate pins, or using Forscan. If you can start in drive the switch should be replaced ASAP, that is a safety issue, aside from 4x4 low.