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Old 10-13-2018, 06:52 AM   #177
78F350
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Join Date: Jul 2014
Location: Oklahoma
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Quote:
Originally Posted by Escy View Post
The fans on a Boxster are triggered by the ECU grounding the trigger wires. You'll likely need a fan controller to do that. Simple and cheap enough.

On the later canbus Boxsters, I believe the last 1/4 of the tank is calculated by the ECU so the level just drops to zero. The low fuel light, engine temp warning light, engine temp gauge and check engine light are all on the canbus.
You have a running, swapped car and I have a partially connected mess of wires. I trust you. Initially I plan to have a pair of simple switches on the dash for fan-low and fan-high (okay... probably one three position switch).

The fans on the Audi A8 are triggered by the HVAC Control grounding the trigger wires (through D7, Brn/Yel). [and there is also a thermal switch on the lower right side of the radiator and the AC pressure switch for fan speed, but lets keep it simple for now.] The HVAC Control has two connections to the ECU pins 40 and 41 on the 7.1.1 and pins C11 and C14 on the 7.1 (Green/Red and Red/Black wires on both). I don't have all my reference material handy, but I expect that they are AC demand to the ECU and a cooling fan demand to the HVAC.

I haven't looked at the details of the fuel warning yet, but I expect that it will be easy to make the light not be lit.
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Last edited by 78F350; 10-13-2018 at 07:13 AM.
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