2001 Ford Windstar, Alternator Burnt Up, Cooling Fans Run At High Speed

This 2001 Ford Windstar came in with the complaint that the alternator was not charging. Simple enough I charged the battery, checked and changed the faulty alternator assembly. The alternator is easy to change but the belt is a bit difficult and requires two people unless you already have the vehicle up in the air. I noticed that the output post in the old alternator was loose. It also had a burnt, crunchy feel to it. I thought that was a little strange so I decided to pay very close attention to the charging system to see if something may have caused this condition. Sure enough there was another problem. I had charged the battery fully with a battery charger so I should have seen charging numbers like 14.25 volts and about 10 – 15 amps output with all accessories off. Instead the numbers were 13.6 volts and 77 amps. Way too many amps with the battery charged and no accessories turned on. I did some checking and found that both of the engine cooling fans were on at high speed. I double checked to make sure the a/c was turned off and it was. I connected my scan tool to check for data related to the fans. Everything looked okay until I looked at a/c data. The a/c head pressure voltage was at 0.00 volts and the a/c pressure was at 0.00 psi.

I did a quick check to see if the system had pressure in it and it did. The next step was to disconnect the a/c high pressure sensor. It is located on the a/c hoses that are at the lower frame rail as shown below.

I check for five volt reference voltage on the brown/white wire, present.

I jumped the brown/white wire to the tan/light green wire and checked voltage on the scan tool. It was now reading 5 volts. I had also confirmed a good ground signal on the grey/red wire.

Jumper wire shown installed in the harness connector.

I installed a new sensor and reconnected the harness.

The new readings and the fans operate as designed now.

The picture below shows the a/c high side pressure switch. It is also sometimes referred to as a pressure transducer.

That one was fixed but no one was happy about the situation in the end including myself. I was happy that I had found all of the problem and fixed it right but there were too many people involved with different interests. Let me explain the chain of events. See Part2.

2 discussions on “2001 Ford Windstar, Alternator Burnt Up, Cooling Fans Run At High Speed”

  1. Any time an alternator “burns up” there is an underlying cause. Some general causes are system drains which discharge a battery and therefore overwork an alternator. System overload which is what I posted about that overworks an alternator and a sulfated battery and /or otherwise damaged battery which again overloads the alternator.I would strongly recommend your mechanic to investigate for the cause of the alternator failure.

  2. My 2003 windstar has a recent issue. Wondering if its common for the alternator to actually burn up/out. My wife noticed a foul smokey smell. I checked under the hood, and found the coils discolored, hot after justa few minutes of running on a cold morning, and later in the day said the baterry light came on. We will be bringing it to repair shop in the morning… Just wanna know if this is common.

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