[Ovmsdev] HUD Connected to OVMS not working

[Michael Geddes]

More information:

I'm definitely getting power on the OVMS -> OBDII cable.  11 volts when the
car is off, and 12.6 volts when the car is on. I'm assuming this is quite
deliberate. (And like 0.2 volts when the power to the ext12v is off).

By default, the HUD was needing (according to docs - probably) 13.2v to
trigger it to turn on.. so I connected it directly to the car OBD and
changed that setting to 11.5 volts.

When I turned the car off (still connected directly).. the HUD remained on
as it was still getting > 12V.. so the setting definitely worked.

Unfortunately when I then connected the OVMS to the OBDII and the OVMS ->
OBDII cable to the HUD - it still didn't turn on. :(  (oh and yes - "power
ext12v on".

Any thoughts on this would be welcome.

//.ichael


On Sat, 15 Oct 2022 at 07:15, Michael Geddes <frog at bunyip.wheelycreek.net>
wrote:

> Hi all,
> Anybody got any experience with HUDs?
>
> I bought this simple HUD from FastTech:
> https://www.fasttech.com/products/9686283
> When connected direct to the OBDII port, it powers on and seems to
> function. When I connect it to the OVMS module with the standard
> https://www.fasttech.com/products/9652027  the HUD doesn't even power on.
>
> It's stated draw is 200ma which afaict should be fine.  I'm pretty sure
> the 12V power is getting to PIN 16... though I will try again to make sure.
> I only have a crappy little Multimeter.
>
> On the Troubleshooting it states:
>    "HUD only available for cars with OBD2 and EU-OBD agreements ... HUD
> Products don't support JOBD and OBDI protocol."
>
> The OBD HUD connector has the following pins:
>
> 4* Chassis
>
> 5* Signal Ground
>
> 6 CAN High
>
> 7 *ISO9141 K Line*
>
> 14 CAN Low
>
> 15 *ISO9141 L Line*
>
> 16 Vehicle Battery +ve
>
> * Long pins
>
>
> These are the standard OVMS supplied pins:
>
> 4 Chassis Ground
>
> 5 Chassis Ground
>
> 6 CAN H (Primary)
>
> 14 CAN L (Primary)
>
> 16 +12V
>
> So obviously the main difference is the lack of K / L lines in the OVMS
> ... but I wouldn't have thought that would have prevented it from powering
> up.
>
> Does anybody have any thoughts on this?
>
> //.ichael
>
>
>
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