Good Morning Guys and Gals,

Head scratching set to maximum here. My 2003 F-550 6.0 dump truck has been working flawlessly. I was working on the next mod for the truck being a F650 lower panel from RiffRaff. I bought a panel for fitment until I get their panel. We have a variety of dump bed related wiring that I chucked up inside of the dash area. In that process, I must have unplugged the connector for my aftermarket radio. No big deal.

I thought I may have blown the fuse for the radio, so I grabbed my multimeter to check the fuse. It showed fine. While in the under dash fusebox, I was testing the mini fuses to make sure I didn't have any that were blown. The only thing out of the ordinary was that there is a 60AMP Light Blue fuse in the upper left of the block. When I touched one of the test points on the top, I heard a "Chirp" similar to what you hear from a security system. The truck is the basic bare bones cab/chassis municipal truck with no alarm, etc.

After a couple of hours of working around the cab, and having the doors open, etc. I tried to start the truck and the batteries seemed weak. I did not get my usual smooth crank over, and the dash lights dimmed when I turned the switch without starter engaging.

I put it on the charger for about 2 hours. Took charger off- truck started right up- all seemed well. Fuel gauge read low for some odd reason. No check lights, tach worked as did speedo. Idle was NORMAL. Put truck in drive and started out. Reverse was fine, as was low gear. Once on the road, truck remained in low gear even though shifter was in D....

Decided to pull over, and shut off truck. Shut it off, and wouldn't restart (Again, suspected low voltage).. I have an SCT programmer- it was showing 13.5 v...

It did finally start and I limped back home in low gear....

Went home, pulled batteries and installed brand new fresh batteries. Turned the key- dash lit up fine, but no start motor. Called my mechanic buddy, and of course while on the phone tried to start truck- fired right up (Thanks Mr. Murphy). Gas gage now read correctly. Engine was running at a noticeably high idle- not normal. I put the truck in reverse and it worked fine, but I had no back-up alarm....
Shifted into drive ( jerk because of high idle) and started down the road. Truck was not stuck in low, appeared to now be in third gear. Drove to stop sign. When pulling out, obvious truck did NOT downshift- just running in third as a perceived limp mode. Brought truck back to garage.

Will check for codes today- but any ideas. I am thinking the tranny programming is weird or maybe a computer issue. I do have the SCT programmer on the truck. Any help appreciated! I know these gremlins can turn into a bitch....

Bruce

 

I'm no mechanic or electrician, but if you pulled alot of wiring, could a simple ground wire somewhere have gotten messed up? I've read many posts over the years, and it seems like a missing or poor ground wire can cause all sorts of weird issues.