Yes, i searched, and searched and read and searched....

For the life of me, i have NEVER seen an issue so prevelant as this one, and still no good answer to the CAUSE and the FIX for it...

I have a BOX of these seatbelt /flasher CPUs.

ALL of them from coupes and convertibles cars that had the same problem...

I know that the NORMAL sound and light operation for these CPUs is...

(the seatbelt light is on all the time during the beeping)
BEEP BEEP....BEEP BEEP....BEEP BEEP....BEEP BEEP....
(the seatbelt light is on all the time during the beeping)

However the problem i speak of is...

Seatbelt light is on...
BEEP... BEEP BEEP... BE... <---PARTIAL BEEP at the last before it repeats!
Seatbelt light is goes off...

-repeat-

Seatbelt light is on...
BEEP... BEEP BEEP... BE... <---PARTIAL BEEP at the last before it repeats!
Seatbelt light is goes off...


When your driving, with the seatbelt ON, the beeping stops, but the light continues to flash with that same 2.5 second on/off/on/off pattern.


The OTHER symptom is, that when you arm the alarm, it wont arm, or it at least resets (within 2.5 seconds).

On a convertible, the headlights revert BY THEMSELVES to LOW BEAM after this same 2 seconds span of time when activated.

now... Lets knock this out once and for all..

MY THEORY:

The CPU is losing power, dying, then coming to life again, then dying over and over and over...

It's as if a component has gone bad in the power circuit is turning off and on with a 2.5 second frequency.

This would account for the behavior i see in all cases.

Replacing the CPU fixes the problem.

SO the problem is IN the cpu.

BUT WHERE IS IT?!

So, whos up for the challenge?
I have a box of CPUs ready to fix!!!!

 

is there seriously NOONE who can at least state that they have this problem and fixed it without replacing the CPU?

 

man
that's messed up!

if you swap CPU's it does the same thing? Have you swapped to a Known Good CPU yet?

 

I mentioned that "Replacing the CPU fixes the problem...."

SO the problem is IN the cpu thats in the car now.

Note, i have a BOX of all these CPUs that have this issue.
I have done this swap about 15 times.

I now have about 15 busted CPUs that need all the same repair.

I'm trying to determine what the problem with them all is....
thay all seem to power cycle.

 

Icemark does repairs on alot of the electronic components for the FC, have you talked to him yet?

 

Now, forgive me if this is stupid, but:

Doesn't power cycling happen because of moisture getting in the electronics? Maybe if you just opened them up and let them dry out?

Just my two cents...

 

same thing happend to me. i let it sit for one day, came back and then the beeping got blurred/muffled, like it wasnt getting enough power to sound the normal beep. drove it fine to work and back, let it sit for another day and then it stopped. next time i started it up, the same muffled beep pattern came back. i just though it was a ground problem so i didnt care. beeping came and went and fixed itself within a 3 day period though. i havnt had the problem with it since. sometimes (once a month) i get that muffled beep at startups, then it goes away.

if you still have the porblem unbuckle your seat belt, let it retrack, then pull it all the way out and buckle it. it seems to help stop the beeping.

im down for this so if you need anything from me dont be affraid to ask.

 

It's bad cold solder joints in the "CPU".

It could also be a bad / dirty switch in the seat belt itself.

This has all been covered before.
Your searching skills suck.



-Ted

 

Harsh.









Not disagreeing though.

 

I'm surprised at you RETed...
My searching skills are just fine (in fact superior in most cases).

So are my component level engineering skills.

I understand that cold solder joints are ONE MAJOR cause, however, this box of busted flasher CPS i have have all been resoldered, some TWICE!

They have bad components on them somewhere that is causing the power cycling.

I dont have my comparitor any more, so i cant take a working one and joint by joint test the differences to see whats bad.

Anyone interested in helping here with some real advanced electronics help, or are we all to assume that somehow I forgot how to use the search feature much less that I have built a few of these cars from the frame up?

 

A couple of things:

#1 Re-soldering a CPU, means you MUST REMOVE THE OLD SOLDER FIRST.

Then flow new solder in.

YOU CAN NOT JUST RE-HEAT a joint and expect that to be considered re-soldered.

Now I am not sure if your "component level engineering skills" know this, they may, but most people do not. Of course with the crappy S5 boards, the odds of even removing all the old solder and flowing new in and fixing the issue means that you might be doing it three or 4 times before it is fixed. (I personally do not even work on the crappy S5 CPUs anymore... they are not cost effective to fix- just buy a new Main board- its cheaper).

#2 it is reporting an error code. Hence one of the switches are reporting an open circuit when it is supposed to be closed. on the S5, 50% of the time this means the switch is bad or the tracks are gummed up, and not a CPU issue.

 

Yes, I knew that about the old solder.

This is the first time i have heard that s5 cars BEEP out any error codes.

S4 cars do, but not S5.

If you look closely at the beeping pattern i speak of, then youll see that it DIES just into the last beep and "reboots" starting over.

(The Seatbelt light goes off too.)

This thing is turngin off/on off/on over and over.

Its like a cap or transistor is cycling.

I have desoldered the entire boards on some of these and removed many (not all) components for testing, but havent found a failed one.

I then resoldered them, testing for resistance from the legs of components to the neighboring leg to see if the solder joint was bad.

All tested good and placed them back in operation only to have the EXACT problem all over again.

Its the damndest thing!

 

this is why I don't even attempt this level of electronics repairs

icemark is my man

 

It's the power seat belt thing that creates the error codes. Only in the USA (no other countries were forced to have passive restraints like mouse belts) and S5 coupes (although the S5 verts use the same main board in the CPU so that is why the vert ones that fail occasionally have the same issue.

Just buy a new main board. I am not convinced that it is not a bad chip.

 

when i go over some bumps, my seat belt beeper goes.. tugg on my belt and it shuts off

 

I doubt any of your skills are adequate.
Unless you have the testing equipment to go test every single electrical component, I would think someone with an ounce of common sense would trash that CPU and get another one?
Nah, that's too easy of an answer...


-Ted

 

That would be a bad switch or shorted wires to the switch

 

wheres this switch
i have a 91 fc with madmouse(auto) belts

 

You know, I just ran across this thread, (in of all things... a SEARCH), and didnt realize that there were a couple more replies here.

Especially the one from you RETed.

For gods sake, what are you doing man?

I did search... I know HOW to search... and to assume that -I- didn't search after YEARS on this board as a member and contributor, well...

is just daft.

I have repaired a "few" of these things at the compenent level, and yes, I understand why Icemark says he doesnt fix them anymore.

They are crap!

I'm just surprised that after all the posting and data that I have supplied to members on this forum, that you feel the need to jump me over my searching skills right out of the gate, like i'm some noob punk.

Whatever...


Moving on... I know this isn't an error code.

The reason is because the if you activate the highbeams, they revert to LOWBEAM "in time" with the end of the beeping cycle.

Also, the Security Alarm, and key/healight reminder dies at the same time, at the end of the cycle.

Only to have all this stuff start working again for the next cycle of:BEEP...BEEP.......BEEP...BEEP.......BE><...

(Remember the last beep dies off audibly, incomplete)

Anyway, now I have about 20 of these things and noone seems to know what the trouble is.

Icemark, since you dont repair these anymore, could you reveal what the top things that go bad on these S5 CPU boards are?

One weekend I'll have nothing better to do and I would like to repair this box of CPU's.

 

it seems like your wanting to do it just to do it, which is admirable but why waste your time, believe what mark says, he had a business repairing our crap parts, and if he was not willing to do them theres damn good reason. why not just use the good one you have and call it a day?

if it's the board thats the problem and not the solder theres nothing you can do

 

I currently have NO working CPUs.

The ones I repaired are looooong gone, and didnt have this problem.

 

My seatbelt beep doesn't even work. Nor does the light. Oh and my brake light comes on when I hit the brakes even though no bulbs are out. (Though I replaced th e incandescents with LEDs so that may be the problem.)

My clock doesn't work... my shift up light doesn't either...

what else...

I <3 My RX7

Cheers,
Cody

 

Bad or dirty switch in the seatbelt retainer...
I think this could also be the CPU as well.

You sure this isn't the PARKING BRAKE light?
Could be LOW BRAKEFLUID.

Resolder warning cluster...

Shift-up light bad or disconnected...

It's been years since this thread resurrection, and I still think your search skills suck.
Which also lead to me questioning your electronics skills...
All of the above have been cover before many times over.


-Ted