I have 98 dodge ram turbo diesel 24v m abs light and brake warning light comes on at the same time my speedometer fails I have changed the reaer axle speed sensor and transmition speed sensors several times with varinng degrees of success. I did have a pcm reflash to cancel a signal from the alternator which helped for a little while. I do believe that the problem is some how related to a signal from the alternator because because when the failiure occures the speedometer moves in relation with the rpms. I have also have observed that this problem is ambient air temparature related in the morniing when it is cooler there is no problem at all.