My 90'RX7 conv.headlights wont dim .I installed a temporary ground on the dimmer relay and it works fine if you pull the dimmer switch in, the headlights come on like they should (passing lights i think this is called)looking at the wire diag.it seems to be the cpu controlling the dimmer is this correct ??? I just bought the car and not quite sure about what i have yet..............any advice would be greatly appreciated

 

Common problem with 'verts that have the SRS (airbag).

Replace the CPU main board. You can find them at Mazdatrix for under $90. You want the FC66 CPU main board.

 

You probably need a cpu rebuild. I have the same problem, just stuck in the dim state. I bought a used CPU and it fixed the problem for a while, but basically it crapped out too. I think you can have Icemark rebuild your CPU to fix the problem. I just haven't gotten around to asking him to rebuild mine yet, since my vehicle inspection place doesn't care about the dimmer switch, just emmisions.


Edit: You beat me to the punch, Mark.

Do you still rebuild them? I have two FC66's. I would be willing to *give* you the extra one if you rebuilt one for me.

 

Not the S5 ones...

Overall, I stop rebuilding the S5 CPUs. They are just too problematic. I can rebuild the whole thing and a year later, something else smokes in it (and 90-91 verts are the worst for that), and then the customer comes back and bitches that it died again.

Even though I only warranty for 6 months (twice what Mazda factory does it for) they expect me to rebuild it again, and I do, because I take care of my customers... but there is another hour + wasted rebuilding it again, plus parts, plus shipping and packing and everything. Rebuilding the S5 CPU just means I loose money, unless I charge what Mazdatrix charges for a new one... and then whats the point of you can buy a new one for the same amount???

So it just was not worth the time involved to do the S5 CPUs anymore.

Now S4 CPUs, I can rebuild and it lasts another 15-20 years. I have yet to have even one come back of them. Much more robust computer. None of the mini traces and funky sansuie prom's that the S5 ones have.

 

Fair enough. I was afraid you would say that, but it was worth a try.

So what you really mean is that I need to eventually obtain an S4 and ditch the S5?

 

LOL, that is a personal decision

 

So once again the S4 is superior... interesting...

 

well the S5 headlight switches are actually better, they fixed some undersized traces there...

 

I thought you were on my side... TRAITOR!

 

well the headlight switch and the logicon are better for S5 models, but the car itself is better for S4 models...

Make you feel better????

 

This? 86-92 Flasher CPU 67-5640-FB01
Or this? 89-92 Horn (w/aibag) 67-5640-FC66

 

fc66

 

That's the Icemark I know and love.