Speedo Swap question

[NeXtras]

Assuming i can get my hands on a gen 1 lightning cluster, i wast to swap out the spedometer, simply so it can read faster speeds.

I remember hearing something about the PSOM? or something like that cause the mileage is stored there correct? is there anyway i can install a lightning spedo and keep my current mileage but also read the correct speed?

and where is the best place to find one?

 

[Skandocious]

Your mileage is in fact stored in the PSOM in the speedo, and the only way to keep it would be to convince Ford to reprogram the new one for you, and I don't think they'll be willing and/or able to even do such a thing anymore. I've heard it just doesn't happen, for legal reasons.

 

[Black150]

I'd start at the JY's. Just the cluster, no 351/harness to go with it? I think you would be able to add miles to the "new" cluster, if that is the case.

 

[Lost]

The lightning is different animal . You can take your center section but will not be the 120 Speedo .

Took one I had apart . You can remove back circuit board and plug into 120 speedo . But I dont know where diff lies .

 

[NeXtras]

soo its really not possible?

 

[subford]

Looking at wiring diagrams and shop manuals it looks like it will work if they are both gas jobs.
If you get one out of a 1994 lightning it should go right into your 94.
The manuals show the same wiring, plug pin outs and the PSOM are the same.

It looks like you could take your PSOM out of yours and plug into the new one and you would still have the right mileage.

I do not know what the others are talking about.

Should be plug and play after the PSOM swap.

The only thing I did not understand is what did you mean by "gen 1"?

 

[NeXtras]

by gen 1 i mean a first generation lightning (93-95)

the problem with swapping a PSOM is my spedo reads up to 90, the lightning reads up to 120. If you just change the PSOM you may get the wront speed, for example, top center of my spedo is 45 and lightning is 60... catch what im sayin?

 

[subford]

by gen 1 i mean a first generation lightning (93-95)

the problem with swapping a PSOM is my spedo reads up to 90, the lightning reads up to 120. If you just change the PSOM you may get the wront speed, for example, top center of my spedo is 45 and lightning is 60... catch what im sayin?

Yes but I think the PSOM are the same in all of the trucks.
They did improve them in 1994 but the old ones from 92 still work.
The Speedometer is a voltmeter and has a different range. I think the 120 speedometer will read right with your PSOM.

EDIT:
By the way the Odometer is separate from the Speedometer and has it’s on ribbon cable that plugs into the PSOM.

 

[NeXtras]

EDIT:
By the way the Odometer is separate from the Speedometer and has it’s on ribbon cable that plugs into the PSOM.

isnt that just the LCD screen though?

hmm i dunno

 

[subford]

isnt that just the LCD screen though?

hmm i dunno

Yes but the LCD screen is the Odometer readout.

 

[Lost]

Subford to the rescue......

Thats what I fugued . I hated to tell him the POsom wasn't tied in some way to MPH .

 

[subford]

I hated to tell him the POsom wasn't tied in some way to MPH .

Please explain what are you saying by that?

 

[Lost]

Please explain what are you saying by that?

I should have added "and be wrong."

I know you can swap the posom. To save milage

I didn't know that the calibration for 120 vs.stock was not tied into the posom for sure or not. .

I knew someone with more knowledge in this would speak up. Now I know .