Where does the power come from and go into abs power booster

If you follow that wire around you'll find the relay and fuse under the pump motor if I remember correctly however the hard pedal is almost always caused by a failed vacuum booster or the vacuum line between the engine intake and the booster, you don't have to disconnect the master cylinder brake lines to change the booster.

1990 Oldsmobile Toronado Specs

depending on your exact model...it can be optional, a dealer may have to order the part. i tried several sites and ive found nothing. seems like a specialty part aka (dealership only part)

Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/stephen_171aeeebef53a898

Hi Rebecca,
Since the AntiLock Braking System utilizes the power (vacuum) boost to operate normally, the ABS indicator should come on if the booster fails. Yes, this means your ABS system is not able to function correctly, but neither are your standard brakes (as the extra pedal effort required to stop will tell you). however, your brakes DO WORK, so driving it to get the codes scanned shouldn't be too dangerous - just be ready to stand on the brake pedal with both feet and leave yourself plenty of room to stop by driving slowly and looking well ahead for stopped traffic. Once your booster is fixed, the ABS light should go off without any special reset or clearing of ECM memory. Good luck and happy motoring!

on that year vehicle or any vehicle for that matter . ABS has nothing to do with power brakes . Behind the master cylinder is the power brake booster , vacuum controlled . ABS is a system all to it's own . Think you may have thing's mixed up . You may have a vacuum leak or the brake booster is bad . Is the ABS light lit on the instrument cluster .

1: inspect all brake linings first.
no pulling left or right braking?
the car has 100% full manual brakes. if the brake booster fails.
(its only and assist !!! for 50lb small folks)
so does it? it takes more pedal pressure but has 100% full braking.
this is no accident its by design.
make sure none of the brake shoes/pads are soaked in DoT3/4 fluid
or grease or gear oil.
and no brake fluid leaks end to end, this is really #1 on all cars.
look, then look again. even behind and in front of the master cylinder.
look at tires (inside for fluid leaks>)
2: do the booster test. did the vacuum hose to it fall off?
or got pinched, or ?

google brake booster test
if ABS system. get it all checked,
if ABS get the ABS scanned.

if you cant stop correctly,,,,???? , dont drive.
get it fixed.

Anti lock has nothing to do with it. the brakes operate without ABS. run the motor then turn it off. pull the vacume hose off the power booster and listen for a suction sound. if none. plug it back and start the car. pull the hose and put your thumb on it. it should ****. the booster depends on vacume to work. If you have vacume to the booster and the pedal is hard, change the booster.(scrap yard)

if something goes wrong with abs the brake system it reverts back to standard system!! If you can pump brake pedal up and hold it and start engine and it drops thats normal.You say low pedal if you go 15mph on road and check where pedal is when brakes apply.Power brakes will push aLMost to floor while stopped but while moveing you`ll almost go to slide or will go into slide if pedal is pushed to floor.Get on some gravel at 10 mph and hit brakes to a complete stop get out and check to see if all 4 tires slid or 2 front or only 2 rear. this will get you closer to problem good luck.

Do you by any chance hear a hissing noise from under the dash? If so, yes, you have a bad booster. For it to do what you're saying, it would almost have to have a vacuum leak. However, if there is a problem with something in the ABS system, you should have an ABS warning light on. Also, ABS can make the pedal fade, but I've never heard of it making the pedal hard. Your diagnosis of a brake booster does sound likely, but I'll admit I can't be sure -- this is an odd one.

did you bleed the master cyl. before or during installation? bleed brakes in proper order?RR LR RF LF? does it have a power booster between master cyl.& firewall?check for vacuum to booster.when ABS isn't working you should still have brakes.suspect power booster diaphram.

i have ran into this problem , but on earlier gm products---check the local dealership or a well known mechanic shop that has all data and check for bullitains. what i had found out was there was some trucks that gm had installed the wrong power booster . not saying your booster is to blame, but may be a great place to look seeing you replaced abs modules ,master cylinder ect---hope that helped out!!