i got a autometer mechanical water temp guage, i've taken off the water pump housing, now i wanna drill and tap to fit the temp guage. I already have 2 sensors at the back of the water pump housing, i dont' know why. This is a s5.

where do i drill and tap?

 

What are the first two holes being used for?

 

i got no idea, but its looks like they go to stock harness

 

1 is for the water thermosensor and the other is for the auxillery fan for AC I believe, not positive about the 2nd one though just going from memory. You can drill and tap on the front of the wp housing below the tsat. Just make sure wherever you drill will not interfere with tstat movement.

 

Yep, second sensor is for the auxiliary e-fan.

 

do i need the aux e fan?

 

i got no idea where on the housing to drill, i wanna keep the aux e-fan. the front of the housing looks to cramped

 

It's not to cramped for the electric sensor...

Where ever you decide to put it....just put it south of the thermostat.