Fred_Koser

iTrader: (2)

I recently purchased a clean '95 ABS unit (FD31 43 7A0) from the Classifieds to replace the leaking stock unit in a '94 (FD04 43 7A0). I was under the impression that it would be a direct swap & a bit bummed to find that the stock '94 ABS bracket isn't even close to fitting the '95 unit. No biggie here, I was able to fab up a simple adapter bracket that retains the use of the '94 heat shield & locates the '95 unit correctly. All was well until I powered up & found that though the two harness connectors are identical, the pin out is not. ABS light is on & there is a significant current draw even w/ the ignition off. Wire colors aren't even similar, so it doesn't appear to be as simple as just moving them around to match. . .

I have wiring diagrams for the '93-'94, but can't find a copy of the '95 diagram to compare the pin outs & see what I need to move/swap/modify. Would LOVE it if someone could link me to a '95 diagram, or better yet, share first hand experience with making the '95 ABS unit play nice in a '94. Thanks in advance!

billyboy

Not entirely sure what happens with the US cars, we found there are a few compatibility issues with early and late harnesses....one that comes to mind - wss getting zapped by the alternator - even though they connect up OK.

Rectification was a total front and rear body harness swap to accept the new diagnostic port up front and ecu in the rear.

If you look on the 4 channel abs thread, there's a pin-out for Au version at least.

Fred_Koser

iTrader: (2)

Thanks - I've dug around that thread a few times, will go take another look. . . ;D

billyboy

95 US one> https://www.rx7club.com/3rd-generation-specific-1993-2002-16/95-abs-pump-93fd-760438/

Fred_Koser

iTrader: (2)

^ Thank you - I just brought that thread back to life to add what I've found:

94 Schematic

95 Schematic

and the Mazda Factory Manual:

95 Factory Wiring Diagram

Both show that the solenoid valve relay on the '95 has changed to a simpler version which instead of grounding the (+) side of the solenoids when open (off) just opens. While there is the same number of pins in each, the '94 uses a common (+) for all three solenoids & the ABS controller in the trunk sends a (-) signal to fire the solenoids. On the '95 each solenoid has a pair of inputs from the controller. While there are the same number of pins & the electrical/harness connector is the same, there are a few pins which do not appear to have equivalent functions - - - Maybe someone else can shed some light on this, but it appears to me that the '95 unit may not function correctly w/o a '95 ABS controller + some modifications to the harness. . .