This 2002 Chrysler PT Cruiser came in with an overheating at low speeds, and while stopped for traffic lights problem, and immediately the cooling fan system became the main suspect in this case, as with airflow across the radiator at highway speeds the engine temperature was normal. Sure enough cooling fan circuit codes were stored in the engine computer but when test at the shop the fan operated just the way they should on both high and low speeds. Regardless we replaced the cooling fan relays which at 100,000 miles proved to have contacts that were burned and well pitted thus presenting a problem waiting to happen, so we called it a day and our customer drove off into the sunset. Several days later I’ve got a call informing the car is doing the same thing again, once more a check of the fan reveals normal operation in my driveway. A closer look and manipulating the wiring near the fan electrical connector proved the fault of the fan shutting down could be duplicated and thus isolated. Turns out the electrical ground circuit at the terminal inside the fan wiring harness connection was faulty, and splicing a new ground circuit to the affected wiring lead from the fan motor solved the problem. This saved the expense of replacing the fan motor to obtain a new harness connector, while at the same time leaving the engine main harness undamaged and got us on the road again with no further problems. Intermittent electrical problems can be tricky to solve at times and often have the phantom ability to hide from detection but generally not forever, fortunately this problem was fairly simple to track down. The take away from this story is that overheating problems should not be allowed to persist and cause further damage, especially on a higher mileage engine that’s head gasket no longer has a sense of humor for an excessive thermal workout, this client took immediate action once the problem was first noticed and in time to keep cost down.