Low voltage on starter cab
So I have a problem I have a Toyota Celica T 18 1.6 from 1993 STI that suddenly stopped starting. I drove this car as my daily and it worked every time completely fine until I didn’t drove it for one day and the next day it didn’t start and it sounded like a CD was thrown out of a radio.
I firstly thought it was a bad battery but my battery was completely full. Then I searched for a broken fuse, but all of them also are alright and then my next guess was to starter, but when we dismantled the starter and put it to the test on its own battery, it worked completely fine and had no problems whatsoever.
We cleaned all the connections of the battery and all the cables and tested all the cables separately if they had ground and everything but as soon as we put the starter back into the car and tested it, it wouldn’t do a thing, and we tested voltage of the power cable that leads to the starter and it only showed 8 to 10 V which seems pretty low, but I’m not expecting in this field.
Is 8 to 10 V too low and if yes, how can I fix the problem?
Thanks and for your help and tips and have a great evening.