Jetta A/C Compressor Clutch Cycling

[Fry]

@BikerFry

9. Check for an 11-volt reference voltage at pin T14/3. The reference voltage originates in the J293 fan control module and can be grounded by |the power control module (PCM) under certain circumstances (typically wide open throttle or vehicle overheat conditions) to turn the A/C compressor off.
   If zero volts are present, the PCM is commanding “compressor off” or the wiring harness is shorted to ground.

My ECU is grounding T14/3 in step 9.

[quote=“97FormulaWS-6,post:2,topic:32996"”]

I’m thinking that the J293 Fan control may not be working properly; check the 11V reference coming out of that to either the PCM or the T14. Read between chassis and whatever pin the 11V output is supposed to be coming from.

Let me know if u need another schematic.

[/quote]

lol damn you’re good! As long as the ecu is plugged in, T14/3 is continuous with ground. If I unplug the ECU, T14/3 is no longer grounded.

I really think it’s a control system problem, as that wire that the ECU can ground to call off the fan control module is cycling between grounded and ungrounded.