2004 ram speedometer doesn't work. ABS light is on. Brake light is flashing. Have replaced the sensor on differential and output shaft . Repaired wiring to rear speed sensor and checked fuses and plug at ABS unit. I'm going check the inside of fuse box next. Any other suggestions?

 

Get the codes read, and see what it is whining about.

 

No codes. The only thing my scanner shows is speed sensor A out of range.

 

That will annoy the ABS and brake systems as well. They really want to know how fast you are going.

On yours, doesn't the PCM gets its vehicle speed clue from the left front wheel speed sensor?

 

I don't no can't find a good diagram of speedometer or cruise systems. I assumed it got it's speed signal from the rear sensor. But I will check the front wheel speed sensor. Thanks.

 

Ok, according to what I am finding, the sensor on top of the rear diff also feeds the speedometer. If you have already replaced that once..... Might be tempted to warranty swap it, and if the problem persists, then you need to check the wiring to the sensor.

 

I've already warranted it once and done a continuity test of the wires. I have repaired an abrasion of the insulation.
. Can the abs controller interfere with the speedometer ?

 

Don't know.... I don't have wiring diagrams for your truck.....

 

http://www.mediafire.com/file/8k5u7y...anual.pdf/file