Jim Warman Posted July 16, 2011 Share Posted July 16, 2011 If you are repairing a concern with ESOF 4X4 and you are at that point where you need to test the wiring for the plate switches, here is handy trick. Start with a switch (known good) from an old shift gearmotor. These switches rarely fail so it shouldn't be hard to rescue one that works.... On earlier trucks, simply plug the switch into the appropriate plug under the truck and use datalogger to monitor the plate switches (there are four - A, B, C, and D). With the switch unplugged, all the plate PIDs will display "open". Plug in your known good switch and turn the armature. It doesn't matter what order your PIDs change to "closed"... it only matters that each of the four PIDs can change in response to the movement of the switch. If one or more plate PIDs can't display "closed", you will find a problem with that circuit (or your "known good" switch ain't all that good). For 2011, you will notice that the plate pids will only display momentarily and then revert to "open" when using the dash mounted MSS (manual selector switch). Yes, 2011 uses the same gearmotor encoder as earlier trucks.... For these, select the "PLATE_PWR_OS#" PID and use output state control to toggle it "on". If you don't do this, it will not display the plate PIDs properly. In either case, if you have a PID that can not change state, you have a concern. Testing this way takes only a fraction of the time that testing each circuit individually will take. Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted July 16, 2011 Share Posted July 16, 2011 Thanx for the tip Jim! I think I have done this but with the new motor I was about to install instead of bolting it in I would "try it before I buy it." Now, I can't remember the last time we installed a shift motor so a known good switch plate is extinct in these parts. Quote Link to comment Share on other sites More sharing options...
Jim Warman Posted July 16, 2011 Author Share Posted July 16, 2011 Thanx for the tip Jim! I think I have done this but with the new motor I was about to install instead of bolting it in I would "try it before I buy it." Now, I can't remember the last time we installed a shift motor so a known good switch plate is extinct in these parts. If you test the system with a new motor and it is just as motionless as the old one, remove the switch from the new motor and perform my simple test. Remember, if the module controlling 4X4 function in the ESOF Super Duty (since 1999 it has moved a few times) doesn't know what gear the transfer case is in, it will not attempt to move. We do, on occasion, replace gearmotor controllers - sometimes because it is always neat to fuck up... but if the gearmotor has failed, it is usually a dead spot in the electric motor portion. FWIW, the 2011s no longer have CW or CCW relays... instead, the module applies power and ground directly to the shift motor... Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted July 17, 2011 Share Posted July 17, 2011 Those relays tend to be the most common problem with that system here in the land of salt and plenty. I regularly find them hanging upside down below the fender well because they were unsecured to make room for other shit by the customer/plow installer/lighting installer. The upside down relays re then exposed to water... salt water... where they fill up and corrode. Quote Link to comment Share on other sites More sharing options...
Jim Warman Posted July 17, 2011 Author Share Posted July 17, 2011 Interestingly.... On the coil spring trucks, the relays were in front of the left battery... (caution, memory thing). I've seen a lot of these relay boxes unclipped and laying in an unnatural state. I don't ever recall having to unclip one of these relay boxes On leaf spring trucks.... the relay box is closer to the BJB. Never seen a concern with those... In our region, damaged wiring and/or the aforementioned motor problem are major concerns. One thing we can agree on... I can't imagine your rust issues.... and you need to spend a few days in the oil patch... Quote Link to comment Share on other sites More sharing options...
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