UPDATE -FIXED Transmission and Speedometer work erratically!

Found one of two wires bad, from rear ABS sensor to harness connector under rocker panel behind driver front tire. Both plugs at ABS sensor and at rocker harness connector good, wire broke somewhere in between. Bypassed with new wire, all systems are operating normally. Respond if anyone else has this problem or has any questions. THanks

Having the exact same problem on my 2004 Ram 1500 Larami 4x4 5.7L Hemi the speedometer is jumping around causing the transmission to shift in and out of O/D on the highway and now the ABS and Parking brake light have come on, I'll check the ABS wires. Thanks for your post.

Figured I'd better update my details to this post. In short I don't have a truck anymore, while I was at work and the truck was off with the doors locked it burst into flames!! If anyone else has had this problem please message me because I'm now truckless and fighting with my insurance company and Dodge on covering a replacement truck.
In short if the problem above go's away without you doing anything to the truck quickly take it into a shop!! That's what happened to me the problem appeared about a week ago then went away the next day and 5 days later, BOOM Flambe truck!

Found one of two wires bad, from rear ABS sensor to harness connector under rocker panel behind driver front tire. Both plugs at ABS sensor and at rocker harness connector good, wire broke somewhere in between. Bypassed with new wire, all systems are operating normally. Respond if anyone else has this problem or has any questions. THanks


Mopar guy,

I have an '05 Ram 1500 5.7L Quad Cab 4x4 I've been driving. It came in with broken rear ABS sensor housing. I replaced the sensor with an aftermarket (plug plugged in hard). Now after driving several minutes I get a chime and ABS and brake lights on. My cruise control is VERY erratic (surges up and down 5 mph), also my shifting isn't where it should be. It also will sometimes kill after first start after moving a short distance then stopping.

Just wanted to post and let you know that I suspect the same problem.

Thank you for your post, I will reply when I solve my problem.

update on erratic speedometer & ABS & brake light.....

I unhooked the sensor, cleaned the connections to the sensor, same problem.

I tapped into the two green wires going to the sensor and sent a 1350 hertz A/C signal (via an antique oscillator--- wave generator). I verified that my speedo held a constant speed at about 60 Mph, no fluxuations what so ever. Therefore my wiring must be good to the PCM / speedo control module.

I pulled out the sensor to find a massive amount of metallic "fuzzy" stuck to the magnet. I dropped the cover (9.25" 3.92 trac-loc differential) to find my clutch packs disintegrated, and my spider gears chewed up. There was chunks of metal stuck in the teeth of the exciter ring on the ring gear. (would explain an erratic signal)

I called the local salvage yards, found that they had a problem with the lock-up differentials.

I was told by the rebuilder that they're a B*tch to get the clutch packs into place, and even an experienced mechanic would have a tough time without the proper specialty tools.