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Where's my buzzer?

Posted: 21 Nov 2025, 21:27
by Rik
Hi,

I've seen many on here complain about the "buzzer of doom". I want that too!

My van doesn't have a audible clue for the warning lights, and as it hasn't been that reliable lately i'm constantly looking down nervously to see if a light is on. So I would like a buzzer.

So my question is: where is the buzzer normally, and is there anything special to know about testing/replacing this part?

Thanks!

Re: Where's my buzzer?

Posted: 21 Nov 2025, 21:31
by R0B

Re: Where's my buzzer?

Posted: 21 Nov 2025, 22:20
by Robsey
It is in the small L shaped circuit board on the back of speedometer heads in vans from approx 85 / 86 onwards.

Image

Image

Re: Where's my buzzer?

Posted: 22 Nov 2025, 23:13
by Rik
Thanks guys, that might be a bit more complicated to fix than I thought.

Re: Where's my buzzer?

Posted: 23 Nov 2025, 04:40
by TwinTurbo
most likely the foil PCB on the back of the instrument cluster has failed.

if it was faulty it would be easy to recreate one from scratch if it were not for the random IC that I can't identify.

Re-engineering it is on my backlog of things to do though and is simple enough with modern microcontrollers.

Re: Where's my buzzer?

Posted: 23 Nov 2025, 13:18
by Robsey
Reverse engineering for the most part should be quite straight forward if you base your design on what the circuit does, not how it is put together.

The main functions are :-
1 -
Buzzer test with ignition on, but alternator light still on.
Buzzer should stop when engine starts and the charge light goes off on the dash.

2 -
Sound the buzzer when there is insufficient oil pressure to operate the pressure switch behind the water pump, AND the engine speed is above 2000 revs per minute.

I have seen crude rev counters with change-up lights on them.
These could be converted to sound a buzzer when the desired rpm is reached or exceeded, and the oil pressure switch is still at rest.

Re: Where's my buzzer?

Posted: 27 Nov 2025, 07:03
by Aidan
I have a bunch of bod circuits both diesel and petrol
send me a picture of yours if you want to try a different one to see if it it buzzes
have you checked it works by running the engine then disconnecting the high pressure sender wiring (2 pin plug in engine bay) and revving the engine past 2000rpm ?

Re: Where's my buzzer?

Posted: 29 Nov 2025, 12:05
by Rik
I wish I had more experience with electrics so I would fully understand what you guys are talking about...

But here is a photo of the blue strip at the back of my instrument cluster:
Image

I don't know if this thing originally came with a buzzer, just assumed all vans would have had it so mine must be broken. Also, I hoped it would just be wired in somewhere and not on this very vulnerable looking strip.

Btw, does the buzzer also sound for coolant level/temp? That's the light that comes on most often for me.