I'm buying a battery switch (for a dual batt setup) for my 2001 f150 supercrew, 4.6L. I have the option of getting a switch that as an "Alternator Field Disconnect" feature that is for alternators with external regulators. It is connected inline of the field wire that connects the alternator to the regulator, and it's purpose is to protect the alternator in case the switch is turned to OFF while the alternator is producing power.

All that stuff is a little confusing to me, I believe the regulator is attached to the back of the alternator, does that make it "external"? I'm more familiar with older trucks that have a voltage regulator bolted to the fender (that would certainly be external). Soooooooo I was hoping someone could help me determine wether I need a switch that has an Alternator Field Disconnect feature, or not!

thanks!

 

I hope that I don't confuse you more than help you but here goes. In the service manual Ford calls the alternator an external voltage regulator type except for the lightning model, which you don't have. the wiring is the large black wire with the orange stripe is the battery output or the wire that sends the energy to the battery this is the large terminal with the nut. then you have a plug with 3 wires all small wires the orange with the lt blue stripe is a 12 volt fused powersupply that comes on with the ignition switch that tells the regulator to start charging because the engine is running.Then there is a lt green /red wire that sends a signal up to youre alternator warning light that the system is or is not working. also ther is a white/black wire that is a jumper from that plug to a single plug that goes back into the alternator and that conects the voltage regulator to the stator output of the alternator.
I believe unless some one else can directly help you with a previous install you will have to look at the actual instalation instructions of both if you do have to cut the FIELD wire for the instalation I don't think you will be able to do that as the field output from the regulator goes directly to the brush holder of the alternator (no external wire) hope this helps.

 

Here's what the instructions for the battery switch say:

These switches are equipped with an Alternator Field Disconnect (AFD) switch to protect the alternator in the event the switch is turned off while the engine is running and the alternator is producting power.
1. Determine that the voltage regulator is not built into the alternator. The AFD cannot be used with alternators having internal voltage regulators.
2. Locate the field wire that connects the alternator to the voltage regulator. This wire will be labeled "F", "DF", or "FIELD" on the alternator and/or the voltage regulator.
3. Cut the field wire and splice in enough wire so that one end connects to F1 on the switch and the other end to F2. It makes no difference which end of the wire attaches to F1 or F2.

So, from your post, it sounds like there IS an EXTERNAL REGULATOR, but has an INTERNAL field wire (which is therefore, inaccessable). If that is the case, I would need the switch without the Alternator Field Disconnect feature, correct?

thanks!

 

Yes I agree with you, I don't think that you can safely cut and splice the wire to the field. If memory serves me this wire is attached to the brushes and is part of the voltage regulaor. Go with the other model.