How to Test the PT Cruiser Radiator Cooling Fan

The PT Cruiser cooling fan is often a common failure point on most if not all the Cruisers. Over the years, there are different cooling fan controls systems, with the control pieces moving around. High/Low speed relays, with or without computer control, TIPM integration, wiring and connector location differences, etc. However, the basic fan has a two speed design and you can at least confirm that the fan itself is capable of delivering air at the low and high speeds following this simple testing guide.

In brief, you need the following access and tools for initial diagnostics:

• Access to the radiator fan’s three conductor pigtail connector
• A test light
• An alligator ended test lead about 12-24” long
• A 12 volt battery.

Here is the process.

STEP 1:
Disconnect the fans three pin electrical connector where it plugs into the engine bay harness. This will expose the three electrical conductor pins on the fan side of the connector, which is the male side of the connector

STEP 2:
Connect the middle pin of the of the fan’s connector to the (-) negative post of the battery using the alligator test lead. The middle pin is always the “ground” of the fan circuit.

STEP 3:
Connect the test light alligator clip lead to the positive terminal on the battery

STEP 4:
Touch the probe of the test light to either of the remaining connector pins, either the left one or the right one. The outer pins are the high and the low speed power connector pins.

BE CAREFUL TO NOT TOUCH THE GROUND PIN WITH YOUR TEST LIGHT PROBE, THAT WOULD CREATE A DIRECT SHORT TO THE BATTERY!

STEP 5:
When you probe both the outer pins, the test light should light. If you touch one pin and get no light, that circuit is open and the fan needs to be replaced.  You should get a light for both pins indicating that there is a complete circuit through the fan windings.

A light indicates good fan circuit

No light indicates a dead fan circuit

STEP 6:
While you have the test light probe on either pin, slowly turn the fan blade. If the light flickers or goes out completely, then the fan has a dead spot in the windings and will need to be replaced.  Once testing one pin, test the other and again slowly turn the fan blade to confirm that there is always a completed circuit with no dead spots.