I read a few years ago that there was a circuit breaker that one could pull on the FEH AWD that would inactivate the AWD function and turn the car into a FWD only. Is that really true and if so, what model years have this hidden feature, and does that cut down the 2 MPG penalty that the AWD has over the FWD? Where we live, there are only a few days where the AWD function is really needed.

The reason that I am asking is that my wife and I went to the Detroit Auto Show (NAIAS) yesterday to look at hybrids with plans of passing our 2007 FEH FWD with 115K miles on to our son who needs a new vehicle to replace his 2004 Olds Silhouette with 165K. We looked at all of the electric and hybrid vehicles made by American manufacturers. (We live in Michigan and could not send the profits on our vehicle purchases overseas.) She prefers the SUV style over the low slung car feel of my Volt. We could not find any new hybrid/electric models that could measure up to the FEH in that area. The CMax is just too small and the others are all cars. We looked at the used market for FEH/MMH and there is very little to be found. Those that are for sale have held their value so well that we might as well buy a new one. So, we called our Ford dealer to find out his supply of 2012 FEH hybrids. He has some coming in any day now so we will check them out.

 

No circuit breaker but you can pull the fuse on the 4WD module but this will turn ON your "wrench' dash icon. This will mask or hide any other problem that could come up by staying ON all the time.

 

If you really wish to do this then the best way is to add an electrical switch to selectively interrupt the rear drive clutch electromagnet circuit. You can prevent the "wrench" result by switching in a resistance equal to that of the clutch windings.

Whatever path you take be VERY sure you have not disabled any Trac or stability functionality. The FEH F/awd system is designed to automatically engage, pre-emptively engage, the rear drive clutch at the times front wheelspin/slip is most likely to develop. The first of these low speed straight-ahead acceleration, the other would be while turning, low speed tight turns or turning while accelerating. In those conditions you want to have as much front tire traction dedicated to lateral forces as is possible. So the F/awd system is designed to automatically move a portion of the engine drive torque away from the front in this situation.

Without that automatic F/awd capability your "FWD" FEH will be fine, perfectly safe, most of the time. It's only when the roadbed traction coefficient becomes questionable, marginal, that the automatic, pre-emptive, aspects of the FEH's F/awd system design might well make a difference,....save your life.


. Most of the time, operating on tractive surfaces, this has no effect other than increasing the stress on the drive line components.

Converting to simple FWD, no Traction control functionality, can be fraught with problems, even hazardous. In this instance when/if the FEH should lose traction you will have lost directional control of the vehicle.

 

Yes, a switch would be nice but splicing a switch in/around the 4WD module located in the center console would be difficult. I've been in there connecting to its output, barely enough room for one hand. Wires are short with no extra slack and I don't think that you can avoid settings off the "wrench" icon as input and output is monitored.