I recently installed a large Ham radio linear amplifier in my 95 Ford F250 7.3 diesel extended cab with a 5 speed manual transmission and when I first transmitted with it the voltage dropped very low(an additional alternator is in the works) and then the odometer went blank then just said ERROR and says ERROR all the time now. Then when I drove the pickup the speedometer went all the way to the end of it's travel, over 90mph when I was probably going less than 5 miles per hour. One of the first things I tried was disconnecting the batteries for a while but unfortunately that didn't solve my problem. I then took it down to auto zone and had them plug it into a diagnostics computer but it said there was nothing wrong. I have the engine block grounded to the frame and all my radio gear is grounded to the frame as well and I have 2/0 cable running into the cab to feed my linear. I have tried doing the thing where I turn the key off then hold reset and turn the key on and the speedometer goes through it's sweeping cycle then the odometer says:

E 08 0

Then when I start the engine it goes back to saying error. I'm not sure if the problem came from the voltage drop or if RF was the cause and I'm hoping that if I find out what the problem is I'll find out the cause. Any idea on what my problem could be?

 

welcome to FTE. i searched and it seems like it was pretty popular to get this error after a cluster swap...doesn't sound like you did that

hang in there and someone will get you an answer for sure.

 

I am guessing on this, but I would say the high RF energy fried your PSOM (programable speedometer odometer module). Try replacing it and then design a shield for it.

 

I just got a truck that had been sitting for 2 1/2 yrs and the speedo & odometer don't work and it says "error" in the odo - where is the PSOM??? I've never heard of this before.

 

unrelated but I have a handheld 2 way radio for my fire department 450-460 Mhz, in anycase when I key up close to the dash on my 1992 Geo Prizm the TACH goes to 9000 RPM. Try a few HAM Radio sites, I have a friend who is into HAM radio, I will see what he knows or may suggest for fixing and solving this issue

 

It is screwed on the back of the Instrument cluster and looks like this.


/

 

Like subford said it on back speedo portion . This happens often . I have sold several posom here .

 

Welcome to FTE by the way from LOST