VP Instrument Panel Woes

[Kurlie1]

Greetings all.


I have 2 Volvo Penta MD2020-D engines in my cat.
I have spent the last 18mths restoring the entire systems as the previous owner had not been particularly interested in maintanance and upkeep. The project is nearly completed but one last hurdel has me stumped.


The instument panels (yes ... both of them) have been damaged. Mostly cosmetic which I have repaired but the port motor tachometer keeps dropping out ie. the revs register only intermittently and...


both hour meters are not registering any reading.


I will attach a photo of the rear of the panels and note that the main wiring loomb/plug is the only connection running back inside.
I have checked for loose wiring etc and I understand that the engine hour meter is run off the ignition switch.


I suspect that some connection/wire has been dislodged and not replaced.


Please excuse my ignorance regarding the electrics ... not my portfolio.


Any suggestions would be greatly appreciated.
Thanks in advance

[Orion Jim]

https://www.cruisersforum.com/forums...ly-262086.html

[goboatingnow]

The hour meter lcd has a habit of failing. Replacements lcds can be sourced on eBay etc. I just finished installing mine

[Kurlie1]

Thanks for the reply. Did the log restart at zero or had the hours still been recording when the lcd's where replaced?

[DougR]

The tach on the 2020 engine is driven by an AC or pulse signal from the alternator.
The signal leaves the alternator on the “W” terminal on a grey/black wire and travels to the electrical connection box on the side of the heat exchanger. From there it goes in the harness on pin 13, still grey/black and up to the panel. Thru the connector and to the tach, still grey/black. The tach also has a solid grey wire in the connector, but on the 2020 it is not used.

Most likely there is a poor connection somewhere in the circuit and that’s causing the issue. You can check the circuit with a volt meter on AC volts. Should be alternator output voltage on that grey/black wire at the tach with the engine running.

The hour meter LED is driven by voltage from the key switch, it gets to the tach on the blue/red wire......switched voltage. If the key is on the hourmeter should be counting. That said, the LED is a bit sensitive and they can fail, but sometime they can also stop working from a little dirt or corrosion on the ribbon wire connections. I have had people tell me that they got their display to work by cleaning up the contacts with a little contact cleaner, and I have also replaced them and fixed the problem. They are replaced by removing the front face of the tach and going in that way. Somewhere on the internet there is a video of this being done.......it’s fairly easy. Even if the LED display is faulty, the hours will still be counted within the tach electronics and the correct hours will read when the display is replaced.

The tach is built by VDO, and the VDO part number for a replacement LED is
A2C00065115. I bought some a few years ago in the US and the cost was about $15 US each.

The coin in the photo is about 2 cm diameter.....

[Kurlie1]

Absolutly brilliant replies. Thank you both.
I have dissassembled the instrument panel and removed the lcd screen.
A UK boat parts supplier asking 45pds ($85NZD) for the lcd but I found them on Wish (exactly the same) 2 for $82NZD includes shipping (ordered).
Also 3 excellent Youtube videos of the dismantling process.
Thanks again

[Kurlie1]

Also I have found that the alternator belt needed a tightening tweek. A bit of slip under load seems to have been the tach problem.

[goboatingnow]

Originally Posted by Kurlie1

Thanks for the reply. Did the log restart at zero or had the hours still been recording when the lcd's where replaced?

No it had the original hours