I'm having the same issue with TOD, but it sometimes occur's when it has not been raining. When your's lock's the front wheels does the TOD light indicate this? When mine does it the front wheels TOD light does not show anything. I'm in Dallas too so maybe we can discuss on the phone. 214-325-0581.

I also use Crest Isuzu in Plano, and they are pricey.