Gentleman:

I read in the owners manual of my 92 F150 4X4 that if you change tire size, there is an adjustment that can be made at the dealership that would correct the speedometer error that would occur otherwise. Can anyone tell me how to do it myself so I could save some money by not going to the dealer.

Thanks in advance.

Rick

 

Some info in this thread from Danr1: https://www.ford-trucks.com/forums/1...-cylinder.html

A great write-up from Steve83: What's a PSOM & how do I "P" it???

 

i wounder if its the same as when you change the gearing in the rear end, you have to change the speedo gear in the tranny. well atleast on aod's you do

 

i have read the whole write up on how to recalibrate to. i found the little module under the glove box, it is baby blue with a yellow wire. it is fastened in the lower part of the dash by one of those plastic tree clip thingys. after i yank the part out, what kind of pin do i use? i have seen alligator clips in videos too. how do i stick a pin in and ground it at the same time? any idea a cheap tool i can make/buy to do this job?

 

bump...

what tool to use and can i ground it to any piece of metal in that area or do i have to do it on the neg battery terminal

 

Read danr1's response in the first link I posted. A piece of wire works just fine. You can ground it to any piece of metal nearby.