I've been looking to get the brain box for my 85 - the one that controls the windshield wipers and such, but for the life of me i cant seem to find it on any of the car's i've gone to take it off. isn't it on the drivers side kick panel? can someone show me a picture of one and tell me exactly where it is?

I've ripped apart 3 rx7's at scrap yards looking - i have to be looking in the wrong place.

I did however, find a brain box sitting on the drivers seat of one that said mazda and some other stuff, but it was MASSIVE, and i really don't think it was correct. it was like 2 inches thick, and like 6 wide by 8 inches long.

I just really want my wipers to return to the bottom on the intermittent setting without me having to hold them, and the first out of the three speeds to work.

 

No brain box for the wipers. Wiper switch and motor unit controls them. Switch most likely needs the contacts cleaned.

 

Wiper bottom position works off an internal rotating switch inside the wiper motor.

Pic:

 

81-85 wiper intermittent circuit, turn signal/hazzard flasher, seat belt timer, various buzzers and other stuff is controlled by the CPU. It is a black plastic box about 2" X 3" X 1". It is located under the left side dash, against the kick panel, above and towards the front of the car from the fuse box. It does not control the wiper stop position or the speeds. More information is in the FSM, chapter 15. I would check both of the issues mentioned above.

 

I'll pull the motor and clean it, just to make sure it's not that. i already replaced the wiper switch and cleaned all contacts. I was close to cpu, dang. i knew it was around there somewhere.

so my wipers not completing one full swipe is controlled by the motor, not the cpu, then?

if i push the wiper arm towards the front of the car do do one swipe, it will not complete the swipe unless i hold the switch - and i let go when it reaches the stopping point.

the first speed out of the three will move up about 4 inches on the windshield and fails to continue or return.

the second and third speed work fine - except if i turn them off the wipers stop wherever they are. hence why i figured it was the CPU.

so i likely need to clean the motor and possibly replace the cpu, then?


maybe i'll go to pick n pull and nab a wiper motor just in case mine is beyond repair.

 

Sounds like it could be a dirty or corroded or worn set of contacts inside the wiper motor; not passing sufficient current to get past a dirty spot.

Those ring contacts carry the motor current, and the "interrupted spot" where there's no copper on the inner ring tells the wipers & the CPU when they are in 'home' position. The outer "wedge" contact provides for startup to get out of 'home.'

The CPU detects the interruption of current, & based on the delay setting decides whether or not to start another cycle.

If the ring contacts are dirty or bad in one place, the CPU would see the current drop out and 'think' the wipers were home, when they are not.

At higher speeds, the wipers may have enough inertia to carry past the dirty spot.

Good theory, at least. Only investigating will see if it's true.

(& is all assuming that the FB is the same in this regard as the SA...)

 

sounds good to me. I'll be sure to take photo's of my motor if and when I clean it. I think I'll nab a spare, clean the **** out of it, re-grease it and install it. then do the same with mine.