re
Either way, I should test alternator output.

that's a good first step.
Should be between 13.8 volts, and 14.5 , alternator charging.
I like to measure it at the battery positive terminal myself.
There is nothing in the main relay to control voltage to the ECU - I sure
don't think there is.

the hyper fast wipers are a weird thing for sure.
but start just like you said, checking alternator output with a volt meter,
at idle, and at elevated rpm.
Scott
----- Original Message -----
From: "neil n" <musomuso@GMAIL.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Friday, November 20, 2009 1:33 PM
Subject: How many volts can ECU handle?

> Hi all.
>
> Although I rebuilt the wiper linkages/shafts not long before swapping
> engines, (Jetta 2.0) and it may be that they are simply working as
> designed, my wipers have always seemed pretty "fast" since the engine
> swap. Like fast enough that putting them on high, is kinda scary! (I
> notice it more now as I tended to drive my Westy in Spring/Summer)
> This lead me to thinking: "maybe my alternator is putting out too many
> volts?"
>
> Seems to me that the principals of Jetta and WBX ECU's should be the
> same in this regard, so.....
>
> Looking at my Vanagon Bentley, I see B+ from alternator going to the
> Digifant control unit relay, then off to the Digifant ECU. Seems to me
> that the amount of volts to the Digifant ECU is controlled only by the
> alternator regulator. (or is there some other limiting component in
> the ECU relay?)
>
> More a point of curiosity than anything, but if an alternator puts out
> too many volts, would this do any damage to an ECU? I figure that
> things like wiper motors etc. can handle a little more, but was
> curious about a more sensitive item like the ECU.
>
> Either way, I should test alternator output.
>
> Neil.
>
> --
> Neil Nicholson '81 VanaJetta 2.0 "Jaco"
>
> http://tubaneil.googlepages.com/
>
> http://groups.google.com/group/vanagons-with-vw-inline-4-cylinder-gas-engines