ABS light/brake light

I know there has been a few threads on this but i didnt find any doing this,
ABS and brake light on all the time, today i replaced both left and right front sensors, started it up light went out, drove it a few miles, hit the brakes, the ABS starts working, by working i mean, you could hear them pulsateing, then ABS light and brake light came back on,when the ABS light is on i have on ABS, shut engine off, start back up lights off drive a few miles hit brakes and at about 8 MPH you can hear and fill the ABS kick in, start again and stop same thing about 8 MPH ABS kicks in this is on dry pavment, had codes read, C0265 comes up, iam told EBCM could be bad, i checked the grounds, talked about on old threads everything ok there,anyone know what should be my next step,iam running out of cash, just put i 654 dollar fuel pump in today also, AC deco pump that is.
Any help ?
(Update) i need to add the scann tool showed the speed sensors reading the blazer was going 3 MPH when it was stopped,just dont know what to do next.

update again, we have a bit of snow, so good time to check out ABS, the lights have been off for 3 days, so i been hitting brakes hard to get the ABS to work, they work fine, after about 5 times of hitting them , lights come on, just shut engine down and restart seems to reset everything, seems to be getting better, this may sound crazy, but i wonder if since they just have not been used in 2 plus years, it just needs a good work out, like i said, its getting longer and longer inbetween the lights coming on, never know

I'm having ABS trouble on my Blazer that is different than yours. thought I would tell you something an older mechanic told me who has worked in a Chevy house for the last 6o years and is still working.

http://www.automotiveforums.com/vbulletin/showthread.php?t=930025

In the early years when Chevy 1st came out with ABS brake systems he had 2 or 3 different Chevy's where both brake lights stayed on all the time. All brakes working properly, the only solutions is to replace the ABS brake box that sets under the hood, but these people did not want to spend the $1500.00 for the part to fix this problem. These 2 or 3 took both brake lights and kept driving.

Maybe yours is going to be like these 3, thought I would mention it for what it worth.

C0265 could be a faulty EBCM but that's rather doubtful, more likely a circuit problem to or from the EBCM. It's not difficult to diagnose, as long as you have a volt/ohm meter, (the flow chart is only 19 steps). C0265 is indicating a problem with the EBCM relay circuit. First step is to check ALL fuses, both terminals, with a voltmeter or test light, with the ignition in the RUN position, engine off. Post your results.

Today I cleaned the sensors, took the ground wire off, cleaned it and cleaned the fuse prongs,when i got in for a test drive no lights for the first 5 miles or so, then when i had to hit the brake just a little fast and hard when a light changed on me, the lights came on, they went off after I should it off and no light again, well for a few min. anyway, the only diff. is now the pulsation has went away at 8 MPH when hitting the brake, I have not had time to go get the guy to put it on the snan tool yet.
I also wanted to say, when at the dealer getting the 2 new sensors, it had a note , ( if hub has a groove worn in it you have to replace it, so the sensor works right) does anyone know where this groove would be, I have yet to see where it would wear a groove in it?
I got a about a 10 page print out today from one of my bubbys, GM data base, iam going to try to go thru that, also iam not sure when you say 19 step flow chart what you mean?
from the looks of all this, it could drive the guys nuts that do this everyday for GM.
would be better off putting black tape over them d--m lights,lol

The way the ABS system is diagnosed in the GM shop manual is by using a flow chart. The chart will instruct you to test something, the results of the test are yes or no answers. Each answer leads you to the next test until the problem is diagnosed and ultimately repaired. For your DTC, there are only 19 steps, maximum, and could be even less, before repairing the problem. Flow charts for other DTC's have 3 or 4 pages of steps. Your DTC, C0265, is rather easy to diagnose compared to other DTC's.

I have not had time to do the flow chat yet, but this thing has went 2 days without coming on and today it came on once,just went on a short run, came home went out again, and lights didnt come on.
will let you know if i ever get it.