Help Needed Wierd gauge action

[bigrigr]

Ok all you 6.0 guys, I have a quick question about my brother in laws 2003 pssd. Obviously it is a 6.0,a automatic,4x4, and a 4dr long bed, and he claims that the dash gauges have gone wacky a couple of times. Once while he was sitting still, with the engine idling, he claims the gauges dropped down to nothing, the stereo cut out, and then the gauges wound around simultaneously, to their max(pegged) position,and then they went back to normal. He tells me that it also did this same thing while he was driving as well. The motor never missed a beat, and everything else seemed ok, just the weird gauges and no stereo for a couple seconds. I'm guessing we"ve got a bad connection somewhere, I'm just wondering if any of you have seen this as well and have any pointers as to where to look first. Thanks in advance.

 

[DaveBen]

This rings a bell, but I can't remember what causes this. The PCM does this for some stupid reason. If I can get the old gears a-movin maybe I can remember what this is.

Dave

 

[JRJ04]

ive seen that happen before when there's an electrical issue...weak alternator, bad batteries, bad battery connections...id check that all out first

 

[bigrigr]

Thanks guys, sorry it's taken me so long to get back to this. If you come up with some particulars, let me know.

 

[Yooper75]

I know weak batteries can cause issues with the electronics on these trucks. I would check the battery connections and grounds as well as have the batteries load tested.

 

[Dogman]

A bad ground will do it to. Need to check all the grounds frame to body, body to motor and so on.

 

[bigrigr]

That's kinda what i was thinking as well, just didn't want to oversimplify this one. I'll pass on the info and we'll see what happens. Thanks again guys.

 

[W4RLR]

My truck did the same thing. Even had the speedo saying I was going 30 mph when I was at a dead stop.

Solution? Replace the original pair of Motorcraft batteries with a fresh set. Problem solved.

 

[lomac9]

My brother-in-laws 2006 did the exact same thing. Threw the help of these guys on here it ended up being a ground. We checked them all and found that the ground beside the battery (pass. side) was the culprit. Its actually happened to him again since the original time and he has had to go back and clean it up again. Does fine after that.