Wiring up thermo fan through microtech LT8

[WHITCHY]

I just bought a thermo fan but I am having some trouble getting it to work?
Does the aux fan control wire from the microtech swith negative or positive?
I was speaking to a mate earlier today about wiring it up and I think I have done it as he told me to do it,
for the relay I have constant power on 30,
and that joins into 86(normally ignition)
87 is power to the fans
and 85 is the microtech control wire.(normally earth)

is this completely wrong?
How do I test if the microtech control wire is sending out a signal?
Thanks in advance for any help!
Cheers.
-Whitchy-

[TurboRA28]

Sounds right to me.
Have you configured the microtech to turn the aux output on?

[trd3sg]

you need to use the handset to set the temperature that the ecu switches the fan on based on the reading from the coolant temp sensor

and the trigger wire from the relay is a negative switch

[WHITCHY]

All sorted! The temp was set at 86 but it still wasnt coming on by 88, Joel told me how to change it so bought it down a few degress and they are coming on now!
Thanks for the help!
Cheers.
-Whitchy-

[-==L=a=N=c=E==-]

yeah the microtech is funny, for the fact it'll trigger AFTER the setup point.

For example, i have my trigger point set at 94 degrees, and it switches on at 98 degrees water temp.

Oh well, worked otherwise.

[The Witzl]

the microtech probably has inbuilt hysteresis for the thermofan output - in that the "on temp" is actually the switch off temp once hysteresis is subtracted.


FYI - Hysteresis is the logic delay variable, ie. if you are defining the conditions of the thermofan with Lance's setup above, the input variables would be:
- set condition = 98deg
- hysteresis = 4deg