ABS and brake light

[Tinovolpe]

I've read a lot of posts on this issue but I can't get a clear picture of what the issue might be with my 99 5.2 SLT Durango.
The abs and brake light will come on periodically. It usually goes off if I turn the car off for awhile. My speedometer seems to be working normally at all speeds but I have had an issue with my brakes locking up. Very annoying and the other day I was leaving a gravel parking lot and the brakes were locking up badly on the loose gravel. When this happened the ABS/brake light was not lit. I'm trying to figure out if it is the speed sensor on the differential, the sensor on the tranny, or maybe a proportioning valve, or the actual ABS module itself. I could just start replacing parts starting with the cheapest but honestly I'm rapidly losing my passion for these things. Between this beast and my Taurus I have a host of ABS issues that make me wonder if all this technology is worth the aggravation and cost.
PS I looked at the brakes on all 4 wheels and everything looks ok, plenty of life left on the pads shoes. Thanks

[Scotty89]

It may be easier of you have the codes checked. Most of the time if the ABS light comes on there will be a code in the module. Even if the light isn't on there can be a stored code if the issue has happened recently enough. It can help point you in one direction or the other. And can be cheaper then just throwing parts at it.

[Tinovolpe]

Update to this. I read somewhere else that the issue could be with the rear shoes sticking to the backing plate. I have never greased those contact points when doing a brak job but decided to give it a try. Had some high temp moly grease and put a dab on each contact point between the shoe and the backing plate. Guess what. The brakes don't lock up anymore and I haven't seen the ABS/Brake light on in over two months. Go figure!

[Tinovolpe]

Finally got to the point where the brake and abs light came on more times than it stayed off so I changed the ABS sensor in the differential. I also took the opportunity to do the rear drum brakes. Made sure everything was nice and clean, lubricated all the contact points like the manual says, new spring kit. No more lights and the car runs and brakes like new. Next step is to flush out the brake fluid. It's only been 14 years