garrett376

Thanks everyone! Adrian, I knew you'd know what that box was - thanks! So maybe my gong relay is fading out!!! Will have to check/replace that and see where it goes from there...

Springer3- I think the temp sensor is on the same panel as the AC unit controls... no?

warmfuzzies

A plain old diode is only to prevent reverse current flow in simple terms it only let's current flow one way.

kevin

springer3

Absolutely correct, there is what looks like an air intake grill on the CCU. So this round perforated disk below and left of the tach is confirmed to be the grill for the gong speaker? I shall listen more closely next time I hear it. In most cars it is somewhere behind the dash. You hear it, but can't see it.

Great board - you can learn something new every visit.

garrett376

Hey Springer3, it appears that speaker-thingy near the tach is a different warning beeper - it only goes off when the hydraulic pressure on my C4 is low and I start to drive around before it's up to pressure - that happens only every once in a while when I'm impatient! I think it might also be used on cars that have a "speed limit" warning - or maybe it's only a C4 thing?!

The "gong" sounded like it comes from the central informer itself when I was tucked under there listening...

springer3

Now we have a mystery. What does it do for a C2? Is it one of the vestigial remains of our C4 ancestry?

Before anyone gets started, I admit I need to get a life!

garrett376

... me too...

JasonAndreas

The warning buzzer usually goes off when something expensive is about to happen (loss of oil pressure). In the owners manual I believe it lists the reasons for activating it. I've had it go off when the ABS sensors behind the wheels got a little too wet. If anyone knows how to disconnect the machine that goes ping I would love to know.

Randall G.

Oh yeah, I had it go off when I got the ABS warning light. Which would come on intermittently, usually after hitting a good bump in the road. Problem turned out to be a lightly corroded ground connection for the control unit. I had never heard it before in 10+ years of ownership. When it went off, it really got my attention--I thought she was gonna' blow!

garrett376

Just a followup - after disconnecting the plugs to the central informer, the gong sounds normal - has not sounded "sick" since. Seems to have done the trick.

Makes you wonder if that should be a regular maintenance item - jiggle the plugs everywhere!!