03 beetle cooling fan issue cycling on and off when AC on

My cooling fans cycle on and off when my AC is on and engine running.Fans do not run if I do cooling fan test with ignition on and ac on fan on low speed. I have checked fan module, check fans, replaced temp sensor, every checks out to be good. Any suggestions

Meaning you get intermittant air coming out of the vents?

Something is amiss here.

Define "checked fans".

Fans should come on LOW speed with A/C switched on (engine does not have to be running, just have the key on). If they do not, there is a problem.

Fans will come on HIGH speed if the refrigerant pressure (as detected by the pressure sensor in the high side line near the expansion valve) sends a signal to the fan controller to do so.

Easy way to check the FCM's ability to turn both low and high speeds on:

With the key ON, unplug the radiator temp sensor (in the radiator tank down low right near the two fan plugs) and jump two of the three wires. You won't hurt anything, just pick two. I forget the colors, but jumping 1 and 2 will make low speed, jumping 1 and 3 will make high speed.

I suspect what is happening is your LOW speed is dead, either both fans' low speeds are both dead, OR the FCM's low speed circuit is dead. So, your fans do not come on low when the A/C is on as they should, but after the pressure ramps up way high, the high speed (which DOES work), kicks on, and that is what you are seeing.

Two speeds, both fans always run together.

I just make sure that the AC refrigerant is charged up. My engine fans wouldn't come on when the AC system was low of refrigerant.

I didn't really notice the fans not running since my ALH engine runs cooler than a gasser. When we pull the trailer the temp gets up over 210 degrees, and then I switch on the AC and the temp drops down to around 190 in under a minute. This doesn't sound right and it appears that I may have the same issue as the OP.

Oilhammer, I will try the jumpers as well. Thanks.

Another question, what does the FCM actually do? Is it more like a relay? I do have a spare one that I can swap out.

1999 is different, does not apply. My above post is for 2000+ ALHs and BEWs.

The 1998 and 1999 ALHs require pressure first before the fans will come on low, and they also have an extra temp sensor in the upper hose for high coolant temp A/C cutout. Sort of a leftover setup from the A3s.

oilhammer said:

1999 is different, does not apply. My above post is for 2000+ ALHs and BEWs.

The 1998 and 1999 ALHs require pressure first before the fans will come on low, and they also have an extra temp sensor in the upper hose for high coolant temp A/C cutout. Sort of a leftover setup from the A3s.

Click to expand...

Okay, thanks for clearing that up. I will check the sensors and see what each one will turn on. I assume I can run the jumper test with the sensors as well in my case?

Sorry for adding my issues to this thread!

Cooling Fans

I had a similar issue with my 2001 Beetle ALH engine. It drove me nuts.
I got the issue resolved when I bought a new control module pictured below.
It sits under the battery tray.
Check on Ebay they are quit cheap. Please do not use the part number from this picture. This is for illustration only what it might look like.