[TXJohn]

Hello Everyone,

Quick question. ESOF Transfer Case shifting stopped working on my wife's 1999 F250 a moth or two ago. I figured today was a good day to work on it. I swapped the motor on the transfer case for a known good one, no joy. I swapped the ESOF relays #1 and #2 under the hood and checked the Maxi fuse #17. Still no dice. It does nothing if I switch the switch. The old motor was in 2 low when I took it off and the dash indicator will show 2 low when I plug it in. Any ideas where else to troubleshoot? Does it look like it may be the GEM at this point?

Any ideas are welcomed!

Thanks!

John

 

[GrampyJim]

Key on, have someone move the shift knob while you listen closely to the shift relays. They will only click if you select a position that isn't already selected. The module will attempt to move the shift motor about 5 times before it gives up. If one relay or the other clicks, the problem is likely in the undertruck wiring (seen a lot of these in our area). If the relay doesn't click, problem is probably in control circuits. IIRC, your '99 will also have a 4X4 module above the glove compartment. The proper manual for your truck can go a long way towards making this repair a lot less painful.

 

[TXJohn]

Thanks!! Sorry for bugging you, what does the module for the 4x4 look like? Can't seem to see anything obvious. The relays are not clicking. Must be the module I don't think it is the dash switch. I had a book, can't seem to find it. It is a 1999 F250 Superduty. Thanks alot for your input. Have a great weekend.

John

 

[GrampyJim]

I'll be passing by work later this evening and pick up my manuals. The only 4X4 module I've had to deal with was about 3/4 thick and maybe 3X5 give or take (old fart memory thing). IIRC, it has 2 connectors.

In the mean time, see if there's any way you can pull up any GEM codes. Also, check the wiring downstairs closely.... especially where it traverses the crossmember and passes close to the front driveshaft - most of our problems involve this wiring and large chunks of the local countryside.

 

[TXJohn]

Thanks!