Hey all! My 84 GS is having some issues and it is a hell of a time trying to chase them, I was wondering if maybe anyone has had these issues before or any insight on where I should start looking/ how to test some of these.

Here is the list:
-Signals/hazards are completely inoperable, with no audible clicking or dash arrows lighting up when either is activated
-Pop-up headlights will go up with the dash switch but won't come down, the headlight stalk will turn on the low beams and high beams but does nothing for the pop-up portion, however, if the headlights are manually set at halfway and you activate the dash switch they will go down then back up, not sure if that indicates anything.
-Wipers are also inoperable, I'm reading no power at the connectors at the motor, however rowing through the modes on the wiper stalk dims the dash lights a little bit.
-The oil pressure gauge is not reading, yesterday I patched a brownish wire which appears to be going from the oil pressure unit to this small cylindrical thing at the top of the motor, I'm not sure if that did anything for it.
-The radio sometimes doesn't work.
-The clock was working earlier but when I hit the reset button, it made the digits go all funky.

Some issues are missing on this list, these are the most severe/ important ones for now.

Any help/advice/ feedback is appreciated!

Thanks,

Midnight

 

repair manuals and wiring diagrams can be found here

Foxed.ca - Mazda RX-7 Manuals

 

Make sure you're working with a good, strong battery first and foremost. Take it out of another car, if necessary. Also DO NOT REVERSE POLARITY doing this. You think you have problems now,...

Secondly, take some time with your battery posts and make sure they're clean, new(ish), and without obvious corrosion. Then, check the Main Power cables for resistance using a digital multimeter. These are the thickest cables going from the battery posts to the frame (*grounds), and to the Starter. Make sure those connections are clean and tight.

From there, you should be getting a solid and constant 13.6volts at the fuse block under the DS left footwell. Once you have that, start looking at the fuses.

Only once you have gold power to the aging electrical system will you be able to trace losses across certain circuits. There are many tricks to troubleshooting electrical problems, but we needed to know more details about this car before you go there. What have you done to it recently? Was it running well before this? What modifications are done to it? How old is the battery? Ever changed the ground and main power cables? Good luck,

 

I got this car at the beginning of June with these issues already, the battery in there is from 2017/18 but is fully charged and fine, the car starts, runs and drives just fine, the first thing I did was clean and readjust all the connections at the battery so those are all mint, there is some chewed wiring near connector X-06 behind the drivers seat, but I don't see any evidence of any of those cables being related to any of these issues, yesterday I tried getting behind the dash panel with the choke in order to check the wiring to hazard/headlight switch but some previous idiot completely decimated the screw holding that in. All fuses are functioning, I checked them with a test light a bit back. all I have done to it is patch a few wires which so far hasn't seemed to do too much, there is no mods to my knowledge except one of the previous owners who ripped out the a/c system. Thanks.

 

The turn signals is probably due to a failed CPU. This was fairly common. If you are lucky, it's just a bad solder connection on the circuit board, easy to fix. The weight of the wiring harness pulls on the leads on the board and cracks the solder joint, it's fairly easy to spot on a close inspection. A diagnostic is if you can kick the CPU with the turn signals on and it starts to work, you have a bad solder connection.

https://grassrootsmotorsports.com/fo...136340/page47/



The oil pressure gauge is common to fail. I never looked into mine, just installed a mechanical gauge. '79-80 didnt have a gauge or even an idiot light, just a low oil level light.

 

had a similar prolem to yours, one fuse had a tiny black spot. barely noticable if you really really looked.

I figured out it was a bad fuse by randomly exhanging fuses.