ABS light on/off frequently

Hi, I don't have the codes, already changed the 4 wheels sensors and the ABS pump ie (used one), but can't get the lights out, I mean (off) on the dashboard. I regret the whole thing and the cost, but it is too late, I did not realize the depth of the cost and problem.
Thanks

Hi there,
I have changed the 4X sensors, and the ABS pump (used unit), but I have new problems, 1-the hand brake light, and 2-engine light stays on, 3- issue, the tachometer is not working, so don't know what happened after changing the ABS pump,
Also to reach the battery terminals is difficult in this car as it's located under the front arches of the car, very unusual place to reach it, must remove the front wheel passenger side in UK cars, and the plastic cover, then to lose the metal frame nuts and bolts, to reach the battery, very small area for movement because of the brakes system parts on the way, you need to work side ways to get to it, so it is not easy for me to do it, I have to see the local mechanic man for it, I am getting very concerned about the cost, already has been over  300+ parts over 100, nearly lost to count the total, all that plus service costs for A MOT ticket, but I am going to gamble on a diagnostic test as last effort to solve the problem, but possibly in few weeks, as I have my work car to use, will let you know soon, later on.
Thank you for your advice.

Not yet, as I explained, the battery terminals are under the front wing, it's difficult to reach in this car, you need to remove the wheel and the plastic shield and the battery housing to get to battery terminals, a bit of struggle for me to do it, with my age being 69 at the present time. The battery is not on the top of the engine bay like the other cars. But since changed the ABS pump, the hand brake and the engine lights stay on on the dashboard and the speedometer is not showing any movement. Need a deeper inspection to solve the problem. I was told the ABS pump is sticky, so I changed it with a used unit. Not much progress at the present time. Let you know later.
Thanks

Hi there, Just pass more information about the situation, since I changed the ABS pump, I have more issues with the car, A. Engine warning light and B. ABS light and C. Hand brake light are on "constantly". Also the speed rev counter doesn't function anymore.