Starting issue, ecu???

[pete_g111]

okay yep i get ya.
when i measure normally i get 12.5V. when i measre across the switch when i start it i only get around 10.5V.
if i short the positive straight to the switch, the starter goes.
Why do you think there is a drop in the switch wire???

[ake]

Possibly yes, unless there is a relay somewhere along it thats failing, but I don't know if or where the starter relay is on a non Pats MK5

[75psT330lwb]

sounds like a poor connection somewhere causing drop in voltage. try checking and cleaning all connections everywhere at both ends and try that.

[pete_g111]

ill check the connections on the switch wire, clean them and post results. thanks guys, im getting closer!!!

[75psT330lwb]

clean the connections on relay aswell and if possible try another one

[pete_g111]

ok, found the relay, checked it out, cleaned connections, looks fine.

now, if I disconnect the switch wire from the solenoid terminal, and measure the voltage at the end of the wire when i turn the key, i get the full 12.5V. But, connect it back to the terminal and i get 10.5V??????? whats going on?

[Altransit]

Something in the path to the switch has a higher than normal resistance, I would try swapping the relay, or look for a chafed wire