You did not mention what year Vanagon it is. I will assume it is a
waterboxer at least. This symptom is pretty common and can have a few
causes.

If a 1.9, the hall voltage comes from the ignition module which is
supplied by the 12 volts from the key switch lead that also powers the
ignition coil. Check for +12 power at the ignition coil black wires with
the key turned on.

If a 2.1, the hall voltage comes from the ECU which is supplied by the
ECU relay which is controlled by the key switch lead that also powers
the ignition coil. Check for +12 power at the ignition coil black wires
with the key turned on. If ok, open the square box on the fire wall and
check for +12 on the stud with the several red wires attached. If ok,
open the relay box near the ignition coil. Check for the relays to click
when the key is turned on. Check for +12 on the red wires going into the
2 relay sockets. With the key on, check for +12 on the large red/white
and large white coming from the ECU relay, the one with the most wires
to it.

Mark

No Name Available wrote:
>
> hey,
>
> I have been helping a friend in the cold rain and snow here in VT with his
> van. He has no spark from coil. so we checked the hall sender (replaced
> recently, by one of the POs). Anyway I proceeded to check for the required minimum
> 10volt signal from the ecu at the hall efect sender wires and I had nothing, now
> the bentley says "replace ECU" in this instance. NO problem, Done< I have
> three good ones. NOPE this aint workin dude. SO Me thinks that we need to replace
> the wiring harness or chase the wires till we find the short or broken wire.
>
> ANy input? previous experience not neccessary.
>
> Thanks
> Chris
> VT