1999 dodge dakota Abs light on and e-brake light on. Speedometer doesn't read untill 25 mph

There is an ABS wheel speed sensor located in the rear differential.
If this fails it affects the ABS and may cause your speedometer to read erroneously at speeds under 25-30 mph. There is also a VSS located in automatic transmission housing. Manual trans vehicles don't have this. They use engine rpm to determine speed as there is supposedly no slippage in the manual drive train.

The problem is the speed sensor in the rear differential housing. Replace it and all the indications will correct themselves.

It is your speed sensor in the rear end...it is used for the ABS system, as well as low speed speedometer readings. I have had the same problem. It will cause the BRAKE and ABS lights to light as well as affect the speedo under 35 mph. It is an easy fix, and can be done by a DIYer or a shop for about $100.00.

This is most likely 2 problems. The ABS/Brake light and speedo issue will be the speed sensor located in the read differential housing. The temp guage issue (and I'm assuming this is at idle) could be thermostat or temp sending unit. The fluctuation is causes by the electric cooling fan cycling on and off to control the temp. However, most of the time this fluctuation should be from about 195 - 220 degrees.

sensor in rear diff may need replaced

when brake light is constantly on it normally means the rear brake light dont work (bulb blown) ABS normally means sensors pushed too far or teeth on abs cv axle could be damaged or bent. check that first.

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it sounds like it is the speedometer cable that goes from the speedometer gauge to the transmission is wearing out.unless you have done one of these before then i would suggest having someone do it for you.

Did you use a mopar sensor.I have fixed this problem many times and not had much luck with the aftermarket sensors.Just a thought.Good Luck!!!

Speed sensor located in top of rear diff is probably bad, It sends a signal to abs module for abs, it also is used by pcm and cluster for vehicle speed.Sometimes rear diff mechanical problem can damage the sensor. Trans sensors have nothing to do with speedo or abs light.