David, congrats to your wife on her purchase. Still don't know if it's a car or truck eh? Don't worry just give it a name I don't know where you live, but dealers might give you a lot of hassle if you want to enable the foglamps. If you live in any of the following states it's illegal. The following info is shamelessly lifted from somewhere on the internet. Remember it's ILLEGAL in the following states:

AL, AZ, AR, CA, CO, CT, DE, FL, GA, ID, IN, KA, LA, MD, MI, MO, NV, NM, ND, OH, SD, SC, TX, WA, WV.

I don't know why you want to look at the wiring diagram. EVERY ML owner knows that wiring the two relays that control the front and rear fogs will do the trick.

Kuan