Anyone have a source for a wiring diagram for the 2003/4 f350 instrument cluster, specifically the wiring/connectors to the gauges? A link to a PDF file would be nice. I would like to try and disconnect the PCM control to the transmission temperature and engine temperature and drive the gauges from my own sensors to bypass the non-linear behavior that ford decided was in our best interest. I am NOT interested in installing any more gauges, just want to control the ones already present with my own signals.

It is possible that these gauges are all addressable devices on a common bus, instead of individual controls. If anyone knows this, that would be good info also.

 

It cant be done. It recieves information to the cluster via the SCP protocol network along with other input information and the microprocessor in the cluster adjusts the guages according to the data recieved via the PCM.

 

That answer reminds me why I don't have a new truck(besides being too poor).

 

This doesn't make in impossible, just more interesting. I have no problem programming a PIC processor to duplicate whatever protocol is required to address and drive the gauges. I just need enough info to figure out how much "trouble" it will be. For instance, if all the gauges share a common bus, then I could possibly "unplug" the gauges I am interested in and create a new bus that I would then drive from the new PIC processor. This would leave the original PCM and bus to drive the stuff I am not interested in changing. I could also create a "dummy" gauge on the original bus to respond to the PCM if it requires a bi-directional protocol, which would be broken if I remove the gauge from its original bus.

I have an engineering degree, both hardware and software, and I am not afraid to get my hands dirty with this project. What I need is enough info to figure out what needs to happen!

If you have any details, or can point me to any documentation on the schematic for the cluster and the required protocol, I can handle the rest.

 

Only place I know of where you could get info is www.helminc.com. I looked up a 2003 f350, and they want $1,450.00 for the cd-rom.

Something is going to happen as far as servicing these new vehicles, but I don't exactly know what. They have this independent automotive service group that represents local service shops. They are crying foul because most of the new car-makers are not being forth-coming with info on how to service the new vehicles. And the aftermarket parts people are not happy either, because no info and specs on how things work, means they can't make replacement parts to sell. The dealers are hogging all the action.

Will the government get involved? Who knows. They are part of the problem, but at least they stepped in and mandated all 96-up vehicles have to use the OBDII standard, so we don't have to buy 10 different code readers.

Do the auto manufacturers have an obligation to release to the independents and public, info on their vehicles? I don't know.

 

Hmmm, this is not good! I was hoping for something I could go to the library to lookup (what ever happened to good old Chiltons manuals!) I have a friend at the dealership, maybe I'll try to get some info from him. I have gotten access to these "cdroms" before on another vehicle, hopefully I can do so again.

If anyone has at least a schematic or wiring harness diagram for the cluster connectors, this would help some.

Perhaps it is possible to get access to the bare analog "wires" to the gauge movement. This should allow a hack to drive the gauges in the analog domain. I haven't quite figured out how to pull the cluster from the dash yet. Any step-by-step instruction available to do this?

I really don't like the temperature gauges having the compressed ranges for reading "normal"

 

I would like to see a wiring diagram for the gauges because I have a strange problem with my gauges. When in Tow haul mode pulling 10,000 lb trailer and my tach reads above 3200 rpm either down shifting or accelerating my gauges wil peg out and back to normal in about 10 secs. and no blown fuses. Also lose power to radio . I would like to know what is tied to gauges.

 

I would check your charging system and grounds. Guage sweep is commonly related to low voltage and radio memory loss at the same time would concur.

 

Yes, I have seen that in several threads, voltage problems causing cluster malfunctions. Could it be your brushes in the alternator could be worn since it only happens at high rpm?