I had my brake light and ABS light on for about 2 weeks, I worked through the whole system replacing pads, flushing fluid, pretty much everything hydraulic. I had read the forums here and those things were always linked to no speedo also but mine was working fine. Yesterday my speedo went also.
I went to the (oops can't say that) and $38.40 later I had part # 1- 56028187AE in hand. ten minutes under my trucks hind end and I now have no idiot lights and a working speedo!!
I shoulda listened here first

 

ALWAYS try the simple stuff first. Glad you got it figured out.

 

Is there anyway to short the speedo sensor wires or something to see if the lights go off before I go out and buy a new part?

 

I tell you what...I am new to this site, but not new to diesel. Ever since I joined the site, I have learned a ton of stuff that I did not know about diesel trucks (I was a diesel mechanic for CAT and compared to some of these guys, I feel like a dang rookie, never stop learning) and the people have been more than happy to answer my questions and give their advice and opinions. I am life time diesel fan and will be staying with this site as long as it is here. Soon as I pick up my next truck which will be real soon I hope I am going to meet up with some of the guys around my area.