From Ford. Though I think this one was from the 11 or 13 year, it applies to multiple years. I have always only gone to the battery for the positive. Interesting that the ham gear handbooks still promotes the fused neagtive to battery nonsense, and even using their flimsey wire that is unsuitable for the under hood environment. Yet, look at Motorola, Harris, etc. and you find commercial and public safety gear instructions to ground to chassis as close as possible to the gear.