Got two simultaneous problems going on with my 1995 F-150 XLT 5.0 V8, 129600 miles. The ABS light just started to come on. Sometimes when I push in the brake pedal it goes down very grudgingly like theres some kind of resistance or its rusty or something; hard to explain. Doesn't happen all the time tho.
Also the speedometer needle has been doing a dance on me. For instance today, while driving a side street at 25 and locking in cruise, the needle was going all over the place, from 15 mph to 30, and cruise would lock, then go out, then back. At 55 or 60, it will go all the way from 40 to 65. At one point today it completely stopped working. I saw another post from a while back on here that it could be a dying battery. Could this be the case? Again, it doesn't dance all the time. Speedo cable going bad? A fuse?
Anybody have any ideas? Just hope this isn't the start of more probs down the road. GREAT truck besides these deals. Thanks in advance.

 

You do not have a speedo cable. The speed signal is taken from the VSS (Vehicle Speed Sensor) located in the top front of the differential. The VSS doubles as the RABS (Rear Anti-lock Brake Sensor.) A problem with that sensor, its wiring or the exciter ring on the differential carrier which it senses could simultaneously explain both of the problems you are experiencing.

Check the wiring repair if required, pull the sensor and clean any crud off of it and re-install. If the problem doesn't go away, pull the cover off the diff and make sure the exciter ring is in place and intact. If all is well, seal up the diff, re-fill it and replace the sensor.

 

Thanks for the superquick reply StrangeRanger. You don't happen to have a picture of the inside of the rear differential would you? That would be a great help. THANKS AGAIN!!

 

No pix. Get a hold of a shop manual for a 93-96 F-150 and look at the differential section. The exciter ring (also called a tone ring because it resembles the one from a banjo) is quite obvious. It is pressed or shrunk into a groove on the carrier right next to the ring gear. If none of the teeth are bent or missing and if it is still in the groove and not wobbling and running crooked, it's OK.

 

Click my black Bronco in my sig & read the captions in the 8.8" Axle album, and these:

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Thanks StrangeRanger and Steve, I got a new ABS sensor at Autozone, 10 minutes later and a zip-tie--as the plastic clamps on the wiring harness wouldn't clamp in--I now have speedo, odometer, no more ABS light and Overdrive ON/OFF flashing OFF. This site is a Godsend to us shadetree mechanics who like to work on things ourselves and seek info and enlightenment. THANKS!!

 

I am having the same issue with a small twist. I have a F150 with the 4.9 inline 6 XL 1995. Its abs light is on and speedometer jumps, just like yours, but here is the twist; it only jumps after I go past 30 mph. For example when doing 25 it stays at 25 but doing 40 it jumps up and down. The severity of the jumps increase with the speed I am going. This makes me think it must be something to do with air leakage. Just where could it be leaking from or into? The rear abs sensor seems pretty snug, should I maybe throw a washer under it, or?.....

Again sorry for bumping an old post found it and figured it would better than creating a new one. Any help would be deeply appreciated.

 

The speedo is NOT air-powered.

 

I have a 96 f150 with the 4.9 2 wheel drive. the Abs light and brake light kept lighting up. then one day the rear brakes grabed real hard while driving down the road. I had it towed to repair shop and was told it was eather the speed senser or the abs controler. I replaced the speed senser whit the ABS speed senser and now the ABS and the Break light comes on and between 35 and 40 MPH the speedometer jumps. Did I get the wrong senser?

 

Blindly replacing parts is the slowest & most-expensive way to fix it. If you can't diagnose it, take it to a pro, live with it, or replace the truck.

Did you read the caption above about the PSOM? Have you read your owner's manual about the meanings of those lights? Have you read a shop manual about how to work on the truck? I recommend an older blue-cover edition of Haynes.