Need help- instrument cluster- speedometer off by 15 mph

[Mark Matulaitis]

2005 ram 1500 4x4 slt. After replacing the factory radio I have a problem where everything works correct except the speedometer. When everything is off and you open a door, glove box, insert the key, etc..the speedometer goes to about 15mph. After approximately 30 seconds it goes back to 0. When you start the truck the speedometer will read 15 mph when you are not moving. Once you are moving the same offset applies, the speedometer reads 15 mph too fast? I've double checked all my connections for the new radio, disconnected, and even re-installed the orignal radio (same thing). One other thing that may be worth noting...I did blow fuse 51 when installing the radio. I don't know what to try next...any help is greatly appreciated.

 

[Oliver Closehauf]

What harness did you use to replace the radio? Probably a long shot, but make sure you don't have 12 volts going to the PCI bus wire.

 

[Mark Matulaitis]

I left the pci wire disconnected. I also tried terminating with an 11k resistor to ground but it didn’t make a difference.