speedometer

[materi]

i recently bought a 96 250. it has 320,000km. (canadian). as i was driving home i realized that evry time i touched the brakes, pulled out the light switch, let off the gas my speedo would jump like crazy from current speed to zero. at low speeds it works fine. any ideas. truck s five speed thanks

[matt morton]

i would say your variable speed sencor is on its way out.located on the top of the rear-end.that is what controls the speedo

[kaptainkimball]

i know this may sound dumb..but i had an 88 f-150 and the speedo would randomly jump all the time. but never truely worked..we replaced the transfer case, and it worked everyday from then on out. a bit of work for a speedo, but i suppose every bit of info helps

[materi]

talked to the previous owner and he said he recently replaced that sensor. his mechanic suggested something about a command start could of been installed then taken out and some wires mucked with. is the speedo just have a cable or is it run electronically? or am i crazy

[matt morton]

pull the sensor out and clean in and put it back in and try it.sometimes there
is dirt or metal on it from the ring and pinion gear.


not sure about the 88 f150

[materi]

i removed sensor and cleaned it there was a bit of crap on it. put it back in and same stuff still happened. i even removed the whole gauge pod and nothing was messed up any other sugestions?

[materi]

problem solved i pulled sensor out cleaned it and realized it was not pushed all the way in.

[fordnut85]

That will do it lol, glad you got it fixed man!!

[materi]

and go figure 3000km later my speedo is acting up again. for awhile it totally stopped working so i bought a new rear speed sensor and still nothing. i was driving and started pushing my cruise control buttons and it slowly started to work for a couple of hours then started the erratic bouncing. Is there anything else on that circuit i can try replacing? and just for info my ABS light is on too

[toads250]

my does the same thing and I replaced the speed senser three time , dumped the rear end checke the ring gear its all okay, I have been told it is the speedo it self the electonics are buggerd up so new guage cluster is the only fix for me I can live with it though hpoe thats helps