M915 speedometer problem

[spartan_185]

Hello,

I seem to be having trouble with the tachometer/speedometer on my newly acquired M915. When I first got the truck, the tachometer/speedometer was disconnected. Now that Ive reconnected it, the speedometer needle will jump from zero to 30mph and then back down to zero about every three seconds. It will do this even with the engine shut off and the key switch turned off. It is also inoperative while driving. The tachometer still works well. I might also add that for some reason this truck has been upgraded to a M915a1 speedometer. Which is totally electronic, VS the cable driven one that would have been on a regular M915. Any help is appreciated.

 

[markmontana]

Bret - you are not alone. I gave up trying to trouble shoot my 915A1 speedo problems (exactly like you mention) and added a good GPS with a big speedo screen.