On the road - Need help locating A/C coolant temp sensor on B4

I posted this thread earlier this week, hoping to solve this intermittant issue before our trip, but recieved no responses.

http://forums.tdiclub.com/showthread.php?t=174434

We are now on the road, on vacation, with no a/c.

Can someone please tell me which sensor is the one that tells the a/c system the engine is overheating?

If it's 2 wires on the 4 wire sensor by the water inlet to the head, which two wires are for the a/c, and what do I need to do to bypass the sensor? Short them? Resistor value?

Much help to anyone that can assist me in bypassing this switch.

-Ben

is the engine overheating ?

that 4 wire sensor is for yur glow plugs and temp guage. just what are yu trying to accomplish?

Is it possible that the system is just low on refrigerant?

Thanks for the response.

The system is fully charged.

When the engine is at operating temp, the a/c will intermittantly shut off.

If the key is cycled, it will run for a while...sometimes minutes, sometimes hours.

The engine temp is rock solid at 195.

What am I trying to accomplish? From my reading here, I understand that there is a coolant temp (or ambient temp) sensor that will shut the a/c off in an overheat situation. I need to know where this sensor is, and how to bypass it.

Thanks again

I also understand these sensors are NOT the same on the A3s and B4s. From what I read here, I understand that the A3s have a two wire sensor in the upper radiator hose that accomplishes this task. I have no such sensor, just the 4 wire at the head.

Thanks again

But if the key is cycled and the AC comes back, then it can't be the sensor, because the sensor would still be indicating a false overheat, right?

-Rich

Nutsnbolts said:

But if the key is cycled and the AC comes back, then it can't be the sensor, because the sensor would still be indicating a false overheat, right?

-Rich

Click to expand...

that would seem correct I think he thinks that the coolant temp sensor is causing his ac shut down, that can happen if his evap freezes up or his highside pressuer gets too high does the electric cooling fan come on when your ac is on??

( ambient temp is outside air temp)

Yes, the electric fans come on with the a/c.

I'm assuming it only takes one spike in perceived temperature to shut the system down until the computer is power cycled.

I've monitored the system pressures when it shuts off, all are within spec at the moment the system shuts off.

Thanks

No one knows where this sensor is?