87 5kcst wiring problem

[Max <mpalmars@axxsys.com>]

Can someone please tell me wether the wires going  to the turbo cooling
sensor (located on the side of the coolant intake spout on the head and
has two pins) are blue or red.  I was reassembling my car after head job
and noticed that on my other Audi (same model same year) the red wire
pair goes to the turbo cooling sensor and the blue wires go to the two
single wire sensors ( one located on the head under the ps pump mount,
the other on top of the coolant intake spout, this wire has a green
yellowish stripe on it). When I tried this on my other (head job) Audi,
it idled at about 1400 rpm's and gave a fault code 2123 ( Full load
switch
    Switch open ckt, stuck closed
    Switch defective (Internal solder connections intermittent) or
wiring problem, ).  The other car shows no fault code with this setup.
Reversed the wires (put the red were the blues were) and the idle speed
came down and no error code.  ????????????????

So which is correct?

Max
Please reply to email adress
2*'875kcst
mpalmars@axxsys.com