My sister recently took her '98 VW New Beetle to First Class Auto in Scottsdale, AZ for an overheating issue.  I'm normally the one who does the maintenance on the vehicle but I was ~600 miles away.  She described the symptoms as follows: overheating light came on while she was stuck in construction traffic and went back off once she was moving again.  I immediately suggested that the radiator fans may not be coming on for some reason.  Since I wasn't around to look at it, she took it to First Class Auto.

She relayed the symptoms to the guys at First Class and also SPECIFICALLY requested they check  radiator fan functionality.

They told her the water pump was cracked and leaking, needed a new thermostat and also replace the timing belt and serpentine belt while they were in there (water pump is driven by the timing belt on this engine--2.0L 8V 4 cyl AEG code).  Well, a) I personally replaced the timing belt, water pump and serpentine belt about 10,000 miles ago as preventative maintenance.  What's more is the car hasn't lost any coolant since the job.  So the water pump being cracked is highly unlikely!  I did not replace the thermostat, though.  Once she called me to tell me this, I told her to decline the work and either take it somewhere else or wait for me to make a trip out.

I had a job to do that brought me almost half way to the Phoenix area so I decided I would make the trip the rest of the way to have a look for myself yesterday.  FIRST thing I did was check the radiator fans.  I turned on the AC and the fans didn't come on at all.  I pop the cover off the strip fuse panel that resides on top of the battery and found a melted 30 AMP fuse.  Guess what that fuse is for?  The RADIATOR FANS!  Imagine that.  Being a car that lived most of its life in Michigan, some of the fuses and the fuse panel itself had become corroded and caused the one fuse and part of the fuse panel to melt.  The coolant level was exactly at the max level, right where it was after I did the maintenance on it 10,000 miles ago, not to mention I checked it before her recent trip to Scottsdale (didn't have to add anything.  The car doesn't leak a drop of coolant).

Local dealer had a new fuse panel in stock, I swapped it out and replaced all 3 of the 30 amp blade fuses as they were all corroded pretty badly.  The larger strip fuses were still decent.  The radiator fans now work as normal and the car does not overheat.  The hose coming off the thermostat also becomes pressurized and hot at the correct temperature as well, so that's definitely not a problem!  Fans also come on automatically once the coolant temp hits 99 deg Celsius like they're supposed to.  Problem solved!

I drove down to First Class Auto today to give them a chance to explain/defend themselves, but there was only one guy working in the shop who she didn't recognize and no one at the counter.  What great customer service!

So she COULD have spent the quoted $800 and STILL had the same problem!  She just got dinged for a ~$40 diagnostic fee... for an incorrect diagnosis.