Many thanks, hope you don't mind that I sent the VIN to you via private message.

 

Had a free hour today so I removed the instrument cluster and test drove it with the alternate PCM installed and with the cluster disconnected. Still drives the same. I'm about to buy/order a cluster, but...

I'm struggling to comprehend how the truck can present the same exact symptoms regardless of whether the instrument cluster is connected or disconnected, if in fact it is the cluster that is bad. To reiterate, engaging Drive or Reverse is very harsh, the truck struggles to get moving like it has a high stall torque convertor - or is starting in 2nd or 3rd gear, and then the brief drop of engine speed to idle every 2-3 seconds while driving unless the cruise control is engaged.

Granted, the only gauges working on the cluster are the oil pressure and fuel level, so it seems the cluster is somehow compromised, but is there any chance of the problems being caused by a transmission control module or something else?

A couple of times I performed data logging, while driving, with AutoEnginuity, hoping the see some clue somewhere, but never uncovered any fluctuations that pointed at anything in particular, not saying they weren't there but I didn't catch anything on the recordings.

I can't seem to locate the proper cluster used and hate to spend about $400 on a new one just to find out that it isn't the problem. I could let another Ford dealership run diagnostics but I'm doubtful that it would be worth the $200. And then there is my pride, which is already heavily bruised. ;-)

I'm looking for a 6C3T-10849-JC or 6C3Z-10849-JC cluster, if anyone has one.

I recorded the engine fluctuation while driving with the accelerator pedal at a fixed position, a link to the recording is just below. Like I said, if I engage the cruise the engine stays at a constant RPM.

I appreciate all of the help so far, does anyone have anything to add? Understand, I'm more of a pre-1980 mechanic than anything, so don't be afraid to insult my knowledge, this isn't my area of expertise. Cheers.

One more question, what if I try a cluster that isn't an exact match, say out of an XL truck, instead of a Lariat? Should the truck at least run normally?

 

SOLVED, it IS the instrument cluster! I just borrowed a cluster from a 2005 F-350 XL 2WD, while not the same exact cluster it allows the truck to run normally. I guess the driveability issues I am experiencing is how Ford wants the truck to run in case someone disconnects the cluster in an effort to suppress the recording of mileage. I guess the part of my cluster that failed was the portion that could mimic having no cluster installed, and mess with the PCM or CAN bus system.

Time to order a new cluster, after I try once more to find the correct used one.

Thanks, everyone, especially (Mike?) m-chan68 and cheezit!

 

Look on E Bay fot it, I see Lariats all the time on there. May save you some money

 

The ic provides the input for vss to the pcm. That controls shift points. Glad the mystery was solved.

 

Thank you for the update. Glad you have your mystery solved.

 

Just a thought, it's less expensive to have one rebuilt than buy a new one. I just had mine done on Tuesday. I didn't have the same issues you did, but my radio and power windows quit working. I chased it back to the wire from the cluster that actuates the accessory delay relay. I found a couple places online that rebuild them, and eventually found someone local who has a mobile business repairing them. He came by my house and repaired mine after he had been to a Lincoln-Mercury dealer not far away.

Glad it fixed your problem. I know how good it feels to finally have something fixed after you've been trying to figure it out for so long!

 

OK I have the same problems as cwc-rummy, cluster goes in and out randomly, windows don't work when teh cluster is down, and the truck operates in limp mode randomly...are you saying it is the instrument cluster itself that is bad? Is the cluster replaceable as a whole? I have a 2006 F-350 superduty.

 

Hey Erik, from my experience, yes, it could be your cluster but since it malfunctions randomly I wonder if it could instead be a loose, damaged, dirty, or wet electrical connection or wire on the CAN bus.

Are you the original owner? I wonder if someone has previously worked on the truck and left something less than perfectly reassembled.

Yes, the cluster is replaceable as a whole. In my opinion, from my experience, the easiest and quickest way to troubleshoot it would be to swap in a different cluster. There are many variations and part numbers on the clusters but in a pinch I found that an XL truck cluster worked well enough in our XLT Lariat to identify the cluster as the problem.