WKeene

Guys, I could really use some help. I can't get my seat belt light to stop blinking. Read a bunch of threads on this but not seeing the same thing. This is on my 91 Vert with standard manual harness.

While this light is blinking, I also get a repeating 4 beep pattern with the safety belt unbuckled. The warning light comes on at the beginning of the first beep and stays on until the last long beep..then goes out. Is this an error code (pwr steering ???).

When I connect the lap belt, the audible beeping goes out, but the light continues in the same timing pattern of on - off as when the belt was not connected.....forever. Never stops.

Here's an audio/video mpeg.

Can anybody help here?

Thanks

WKeene

Really trying to figure this out. Tried FC3S.org code check routine, shorting the green error code jumper to get any error codes.
- Before putting key in the ignition, the security light blinks ???
- After ingnition set to on, the engine light stays illuminated...never blinks. (security light goes out)
- I did notice that I was able to get the round key light to blink at the same time with the seat belt light ???

Man...I'm confused????

Kenteth

haha... i read the topic and was like... what an idiot, blinker's aren't run off of belts...

bahh,im tired

WKeene

You mean this isn't caused by my Alternator belt going bad????? cute...real cute.

Anybody else have any unique perceptions?

WKeene

Is this just too stupid for people to respond to? This blinking light problem bugs the crap outta me....

Anyone dare to make a suggestion?

Kenteth

actually theres been a couple threads in the last week about it. Interesting how we all have PD fires the same week, and then the next week everybody notices there belt light flashing

WKeene

Ah yes...but I caught that nasty leaking PD before my car went up in flames....maybe that's what caused my light to start blinking.....or better yet.... That was on my 86...it must have told the 91 about it....and caused the light to start blinking....yea, that must be it!

At least this is more entertaining than just writing "bump".

Kenteth

lol... hold on

Kenteth

still holding? I was searching and then lost this thread, then my laptop over heated, and then i couldn't find this thread again... augh. ok well just do a search on belt light, or the like. Get the fsm and debug it from there maybe

WKeene

Been reading through the wiring schematics in my 1991 workshop manual. (Warnings & Auto clock, Sound warning control system) Schematics show the Seat belt switch connected to the CPU but I can't find the logic shown for the CPU.

The Self diagnosis function chapter shows the long and short pulses for many different codes....but I didn't see any mention that these would be outputted to the seat belt warning light....

Am I looking in the wrong place? Does anyone know where Icemark got the 1beep-5beep decoding scheme found in his sticky (FAQs)?

Kenteth

logic... cpu... mazda?

Icemark

if you look at the 91 wiring diagram, the light is triggered by the Green/Black (1T) from the CPU.

The input into the CPU is the yellow/red (1Q).

So this is pretty basic. If you disconnect the Yellow/red does the problem go away???

If it does, then the problem is the seat belt switch.

If it does not then the problem is the CPU or someone has added modified the wiring in the car.

You have not swapped CPUs or added any wiring correct??? If so then I would suspect that the CPU needs resoldering/rebuilding as it is reporting a passive belt issue (which if you have a 91 'vert- it should not have passive/mouse belts).

WKeene

Alright...now we're getting somewhere.

Yes, the CPU was changed out by the original owner. He flooded the inside of the vehicle (rain...I don't know) and toasted the CPU (on the passenger side ...foot area). This actually caused a problem with the oil sending logic and toasted the engine. New engine dropped in and a "JUNK YARD CPU" was used.

If the firmware on the CPU was not from a convertible, maybe it's incompatible with the non-passive seat belt restraint...I think this is what you're saying.

If this is the case, can I get that reprogrammed or am I screwed?

I did check the continuity on the seat belt. Unlatched = continuity, and Latched = open....per spec.

What next?

WKeene

Wait, I better get my facts straight. Just read another thread....CPU vs ECU. I'll need to verify which was replaced....

91 Vert part numbers?
- ECU
- CPU

Gotta check on these.

WKeene

Part numbers:

89-91 CPU
* Coupe - FC01-67-560A
* Vert - FC66-67-560A

89-91 ECU
* Coupe - N350-18-88-0 (Cal)
* Coupe - N351-18-88-0 (Federal)
* Vert - N352-18-88-0 (Fed)
* Vert - N353-18-88-0 (Cal)

Just need to check what I've got...

Icemark

The CPU is in the drivers kick panel.

The ECU is in the foot area, but would have nothing to do with the seatbelts.

The CPUs are not interchangeable, if you use the CPU for a coupe you will have problems as it has the passive/mouse belts control and warnings as part of the CPU.

And you can not reprogram a CPU prom. You need to use the correct CPU for the car (SRS+vert= FC66).

I normally have all the CPUs rebuilt and in stock at my website store, however I am all out of the FC66 right now and don't know when I will be getting any in.

WKeene

Well Crud...

I do have the right CPU part number FC66. I was actually hoping to have the wrong one so I could get piece of mind that I got the root cause.

I guess it was the ECU that got swapped out...not the CPU..makes sense that the ECU would get flooded ...not the CPU.

I'll try checking the wires....per your suggestion, Mark:

"The input into the CPU is the yellow/red (1Q).

So this is pretty basic. If you disconnect the Yellow/red does the problem go away???"

How do you disconnect the wire from the CPU..haven't looked at it yet? Are there individual releases for each wire?

But even if that gets it...that doesn't explain why it is blinking and I haven't nailed the true reason for the problem. Beyond that..any other ideas?

WKeene

bump

Icemark

Try resetting the CPU (unplug it for a half hour). See if that solves the problem. If not, then I would resolder/rebuild it and try again.

WKeene

Mark, I unplugged the CPU to reset it. No change. Light still blinks after connecting seat belt.

I cut the yellow/red wire ,1Q, (couldn't pull out the individual connector pin). Doing this (opening the circuit) just acts like the buckle being connected (an open shuts off the beeping). However, the light still continues to blink. Obviously the audible portion and visual (blinking ) are on a different circuit. Or, the blinking is a function of some other message being sent to that lamp.

Unfortunately, I broke the wire too close to the connector and now can't reconnect it. Any suggestions on how to pull that metal connector out of the plastic housing so I can resolder the red/yellow wire?

You also recommended resoldering/rebuilding the CPU...does this still make sense?

WKeene

bump

Icemark

The stock plugs all use a plastic retaining tab for each wire connector. You will have to use a pin or small pick and push the retaining tab up and slide the wire connector out the rear of the plug housing.

Yes, my next step would be to resolder the CPU.

WKeene

Mark, thanks for the tip on getting the connector out of the housing...got that repaired.

I took the PCB from the CPU into work to look for cold solder joints using a 100x - 500x microscope. All joints looked really solid. There were no gaps whatsovever between the solder and lead. While looking under the scope, i pushed on the leads with an x-acto blade....again, they're solid.

I did notice a few small contaminants that may have bridged between the pads(removed them)....don't think they were significant, though.

Really hesitiating to resolder everything. Cold solder joints are pretty obvious...aren't they? ....I'm not seeing them.

downwinddave

I solved my problem by buying a new CPU.

All the time you have wasted, you could have mowed a few lawns and earned enough to pay for it

WKeene

Dave, what were your symptoms? Were they exactly like mine, shown in the mpeg with a very repeatable blinking ...not intermittent?

Anybody have a FC66 CPU they want to sell me or loan to me to debug this? Will send back once I've determined if it repeats or not. I'll pay for shipping.

Thanks...