RustX7

A little backstory: This is in my 87 TII. I have my radar detector set to display voltage, which is consistently up around 13.5 (unless my RPM's are very low, in which case it drops to 12, which has never seemed to be a problem.) And, I recently tried replacing my dash warning light cluster to see if I could get the clock to work properly, but I discovered that it was the connection on the back that was not connecting consistently, because I could press on the harness and get the clock to come on but when I'd let go and nudge it at all it would turn off. So I said **** that and let the clock stay broken. And finally, my E-brake light is always on now since my e-brake handle is slightly out of adjustment (though I'm certain the ebrake itself is not on.. long, unimportant story there.)

NOW... since attempting to replace the warning light cluster, I now have two lights on: e-brake, which is normal, and the CHARGE light (despite, as I said, having my voltage be constantly at 13.5.) This doesn't really bother me, since I think it's nothing to worry about... it's just a new thing.

Here's the real gremlin: Yesterday I noticed that the little FAN light LED thing that's on my temp gauge was going on and off sporadically. This never happened until yesterday. The temp was fine (like midway where it usually is), so I'm like, whatever... that's weird ... THEN, I noticed that it's coming on at EXACTLY the same time as my Shift-Up idiot light. I test it out by revving up in whatever gear, and sure enough, the two lights are tied to one another. AND... to make matters more interesting... when the FAN and SHIFT UP lights are on, the CHARGE and EBRAKE lights on my warning cluster turned off.

Does anyone know if this is something I can fix, or if any of this even really matters in terms of the car's health?

WonkoTheSane

iTrader: (2)

Just out of curiosity, have you tried freplacing your known bad light cluster with your known good one? it's only 4 bolts.. Try the obvious, then get the experts involved.

It sounds to me like either the solder connections or the PCB itself is getting flakey on your light cluster. by pushing on it, you caused more problems, and now are dealing with them. I'd attempt to replace it with the known good one.

I cannot help any more than that.

IceMark would be the one to seek.

RotaryEvolution

iTrader: (30)

resolder the ECU (black box behind the driver side kick panel) and the clock PC board like Wonko suggested. that should take care of the gremlins hopefully, most at least if not all.

Icemark

Any voltage under 13.5 volts while the engine is running is very very bad, and suggests that the alt or its wiring is bad. That needs to be fixed before anything else. Infact ignore any other issues until the voltage problem is fixed.

And the ECU would have nothing to do with it. The ECU controls the ENGINE.

The CPU on S4 models has a alt warning circuit that will activate at under 11 volts. On S5 models the alt failure warning circuit is in the clock/idiot light panel.

If the CPU is bad on a S4 model or needs rebuilding, the idiots lights will not all come on if the key is switched on, but the engine is not started. If the key is on; they should all come on if the CPU is working correctly until the engine is running.

However it does sound like your clock/idiot light panels also need rebuilding of replacing. And that perhaps you are putting the wrong panel in.

I have rebuilt CPUs and clock/warning/idiot light panels on my website.

rexxer

Uh oh, my voltage is always just above 12, but I do have an amp drawing power. Is it still bad for the car?

Icemark

Yes.

Voltage needs to be at least 13.5 volts to even charge the battery. If voltage is only at 12.6 volts, then the car is using the battery to run instead of just for starting as it should.

iceblue

As stated for a new clock dummy light assembly try www.mazdamark.com for a replacement. I do not have first hand experience yet but have heard only wonderful feedback on the products from other members.

RotaryEvolution

iTrader: (30)

the CPU is what i was referring to, i hate how close they term it in relation to american car CPUs....


might want to clarify that is with no loads from any accessories on. the FC alternators blow brown mud and can't put out those numbers at idle with even a few accessories active.

RotaryEvolution

iTrader: (30)

added to ^ post

Icemark

Okay more clear:

Even with the air conditioning on, rear defrost, and headlights, with the engine running at idle (650-700 RPM) the voltage needs to be at least 13.5 volts.

anything less and the alternator is broken, worn out, or has wiring issues.

I do not understand why people don't get this.... You need at least .9 volts to charge a battery.

And the stock FC alts are perfectly fine for stock electrical systems.