I have a few 89-91 flasher CPU modules that all seem to reset every few seconds.

Beep, Beep, Beep, P a u s e... Beep, Beep, Beep

The alarm fails to arm, etc.

Each flasher has the same problem, and now my main, daily driver has this issue.

SO.. its time to determine the problem.
Its clearly somthign common and perhaps there is someone out there that knows the failed component?

Anyone?

If i can find out, I will fix them all......
Then sell them!

I'm already gathering a mass of 1991 wheel center caps and restoring those to BETTER than factory.

 

Do you mean the alarm system light?
Mine works great, when I have a day off to troubleshoot it.
On work days, it's about 50/50.

The seat belt system does the same thing.

I plan to pull & resolder the CPU this weekend..

 

Yes, I mean that, but mostly the seatbelt/alarm/flasher CPU.
They are all controlled by the box in the driver side kick panel.

I need to know what component fails in these, its not a re-soldering issue.

 

The problem is not in the CPU, but in the car.

Probably one of the latch switches (like hood, door interior latches, trunk/hatch) are not closing all the way, or there is a broken wire.

 

I had a problem with my turn signal flashers, My left signal stopped working. so I went down to the junkyard and got a new controller, on the driver side, there is a box down by the fuse box, under the plastic "kick pannel" I just pulled the cover off, turned on the signal that was working to determine which piece was the relay. then I replaced just that piece, my turn signals work great now... just wish I could say the same about my windshield wipers!

 

Thanks, but I know whot to replace.

Its the REPAIR that i want to perform.
I have 9 of these suckers, all with the same issue.

I need to know if anyone can determine what has failed on these devices.

When I gathered enough Wiper switches like this, then I repaired all of those and sold them with upgraded relays.

I want to fix all of these flasher CPUs.

 

do you have anymore wiper switches?
with mine, the relay had failed. it was cheaper to get a used one, then to buy the new relay...

 

I am out of switches and dont have time these days to fix them right now.

I have the relays.

But i really need the repair procedure for the Flasher CPUs.

 

Mark is probably right, and I suppose I'll have to test out the door & sholder belt limit switches also.
(Not fun)
(Of course, if it works afterwards, it was fun.)

BTW any DPDT relay will fix the wiper switch.
Just use some short jumper wires to connect the relay to the board.
Burned out micro relay on the left, heavy duty relay on the right..

 

To repair the flasher boards in the CPU you just replace the relays and remove and resolder the connections.

But the flasher board is just one part of the CPU. There is also a main board that controls alarm functions, key lights, warnings, etc.

And the flasher board would have nothing to do with your beeping as mentioned in your first post.

 

I rebuild and have wiper switches in stock on my webpage.

As well as all models of the CPUs, Logicons, etc

 

Uh..
Maybe there is there some confuusion here?

Its not a broken part in the car.

The flashers WORK fine.
its the ALARM and Seatbelt and Courtesy light at the steering column that is the problem.

They turn off and on and off and on.

I cant arm the alarm.
The seatbelt/headlight/key beeper go:

beep, beep, beep, be.... pause...beep, beep, beep, be.... pause....beep, beep, beep, be.... pause

The problem resides completely in the the little box behind the kick panel on the driver side.

The switch in the pictures above is in the Headlight switch.
This is not my problem.

I KNOW the problem is in the flasher CPU.
I have made the replcement 10 times in the last 2 years on various cars.

Each time the solution is to replace the flasher CPU board/ whole unit.

Therefore whether or not its the CPU or not isn't is question.
It IS the flasher CPU board that has a bad component on it somewhere.

Resoldering doesn't fix it.

What I dont know is what part(s) need replacing on this flasher CPU board that fixes the problem.

Hopefully I wont have to go across town, get another working one, then use my comparitor to compare the two to see whats different.

that would take about 2 hours.
(But would probably answer the question.)

Ignoring the fact that I have to find the time to drive across the state to get the working one.

 

let me repeat, its not the flashers that are bad.

Its the alarm functions, key lights, warnings, etc.
board in the flasher CPU.

Somthing went bad on that, and thats the answer I need to fix 10 of these bad units.

 

Okay, but you keep saying the Flasher CPU. The Flasher CPU is a seperate board in the CPU itself. It is Mazda P/N: 67-5640-FB01

The Flasher CPU Board has absolutly nothing to do with the alarm functions.

Now, the S5 alarm functions are controlled by the Main CPU board (P/N 67-5640-FC01). NOT the FLASHER CPU.

The problem you have descibed happens either with an alarm latch switch or a input from the seatbelt warning circuit.

So if you are sure that it is not related to the car(s) then it is related to a failed input in regards to one of those two, be it on the circuit board or connector.

I would bet even money that there is a burnt trace on the MAIN CPU BOARD (NOT THE FLASHER CPU BOARD) near or under the BUZZER, as I have rebuilt quite a few FC01 CPUs (both the Flasher CPU boards and the Main CPU bpards) and seen that trace burnt.

 

i'll check that, but you must remember that I have fixed 9 other cars with this problem.

FC01 is the coupe
FC66 is the convertible

If the 'vert has this same issue, the turn signals wont work unless you hold that "antenna" arm down.

I know this becuase each of the 9 cars have all been repaired when i replaced the flasher CPU box.

I know that there are 2 boards in this box.
one is for the flashers.

but the entire box is what im used to repalceing so i called it by its name, (embossed on the side)
Flasher CPU.

Somthing on that board (the big one inside) is bad.

When I swap this uit out with a neighbors, it fixes the problem.


The problem is as if this board is losing power repeatedly.

turning on/off on/off.

hence the reason that the beeping is a 'half beep" right before it starts over.

Its a common problem.
Ive seen this alot.
Somthing on the board is power cycling.

 

antenna arm??? what antenna arm???

And how are you re-soldering... I see a lot of cold solder joints, but never have had a board cycle as you say.

 

yes, the turn signals on the 'vert are sometimes called "antenne" like an ant.
they work differently from an NA or Turbo switch.

 

The regular turn signal switch for a SRS equipped vert, you are calling an antenna???

 

i know i know....
confsuing, however its what all the guys here call them.

I forgot to "de-localize" the terminology.

These turn signals work on pure logic circuitry, not electro mechanocal solenoids to release the signal after the turn is complete.

 

Send me one of your CPUs that you claim is doing this problem. I'll rebuild it for you for free just to see this problem that you are claiming.

 

oh boy.
I appriciate it, and maybe i'll do that, but we are in opposite parts of the country, i am going to get a working one this weekend and compare them.

I'll fill you in on what I find.

I'll publish the fix ASAP.

Im floored that i can see 10 cars with this problem and noone knows the answer.

Again, its as if the board is losing power over and over again.

this causes the alarm/seatbelt light-warning/ and light on the steering column to turn on and off over and over.

 

See I am skeptical about the problem. I have been rebuilding CPUs for 2 years now and not once ever seen all the problems in one CPU that you are describing.

So if I could see one, I could tell you what the problem is, but without one... stuck.

Perhaps it is that burnt trace I have seen a couple times. I don't test one until I have already rebuilt it and it is working fine.

Remember you can't just re-heat cold solder joints. that you must remove the old solder first. Then flow new solder in

 

Yes, im aware of component level repair teqhnique.

I can perform surface mount soldering by hand.
This is also why I own a comparitor that lets me analyse one circuit/component against another known good one.

Anyhoo..

Both my coupe and my mothers convertible had this issue.

I'll do what i can to send you one, pm me the address.

 

My S5 has similar intermittant problems with the seat belt & security systems.
I plan to troubleshoot them soon, so whomever gets there first wins..

 

I pulled the CPU (aka flasher) last night.
Found - corrosion around 5 parts in a 3/8" area.
When cleaning with a soft toothbrush, a 37mfd cap just pushed off.
It's lead was erroded away.
All is cleaned up, resoldered & sprayed with clear lacquer.
Results & pics next week.