Be Aware When Testing the New P/D Alternator By Alan Melton One of the new P/ D alternators came into a parts store a few days ago and they tested it with the S/L_ test lead. It tested bad, faN and they ordered a new one from their rebuilder. They unknowingly ruined the original equipment alternator. They tested the rebuilt alternator, again us- ing the S/L test lead, and ruined the second alternator. Then they bought a second new alternator from their rebuilder. When the third alternator arrived we were called to find out what was wrong with the alternator test bench. It took them three alternators to call and find out that what they were doing wrong was using the S/L test lead on the new P/D alternator. This instantly ruins the half of the voltage regulator located in the alternator. There are three new OE alterna- tors in 1999 production being used by two different car manufacturers, Mazda and Ford, that have the same plug as used on other alternators but the terminals are marked differently because they are wired differently. It is very important to know what the ter- minals are on this new P/D alternator, as well as all the others. These new P/ D alternators cannot be tested with the same test lead as used on the other alternators. The problem involves the fact that there are different versions of the same plug used on cars in production today. These alternators have terminals marked S/L, I/A, F1/F2 and the new terminal marked P/D. When the new ? terminal labeled P/D is tested with the test lead normally used for testing S/L and I/A alternators, which 1s what it looks like it should and could be do- ing, the half of the regulator inside the alternator will be ruined. Refer to the chart for the four ver- sions of the same terminal of plug as shown. WAThas let me use their chart that indicates alternators using the S/L and the I/A can share the same test procedure. The S/L terminal is used on 212 alternators. The I/A terminal is used on four alternators. These two alter- nators test alike. The F1/F2 terminal is used on seven alternators and the P/ D terminal is on two alternators with more to come. The chart of the termi- nals also identifies the plug code for each unit. The S/L unit plug code is 300. The I/A unit plug code is 301. The F1/F2 plug code is 302, and the P/D plug code is 303. The first alternator uses a terminal marked S standing for sense and L standing for lamp or light. That inter- nally regulated alternator has hundreds of applications with the S/L terminal. One connection senses the presence of a battery and the other is the charge light. The second alternator, which has terminals marked I/A, is internally regu- lated and used on Ford products. I stands for lamp and A stands for the sense terminal. The third alternator is used on Chrysler cars with terminals marked F1 and F2. These are short for Field 1 and Field 2. The regulator for that al- ternator is external and located in the computer. It bears repeating again that the P/ D plug is a brand new alternator with half of the voltage regulator in the al- ternator and the other half in the driv- MARCH/APRIL, 2000 ing computer. That is what makes it unique. If you use the alternator test lead, which you would normally plug into the S/L terminals or the I/A termi- nal, you will blow out the regulator cir- cuit inside the new style P/D alterna- tor. There are no aftermarket replace- ment parts available yet. When I checked with the Mazda dealer the part was quoted at $185. The P/D unit is used on Mazda Protégé, which was avery popular car from 1997 to 1999. Now we are finding the same unit on the 1999 MXS5 Miata and also on a Ford Probe. The original P/D alternator bears a tag which identifies that the unit is a P/D unit along with the following per- tinent information: 1-Plug Code 2- Vehicle Manufac- ture Number 3-Alternator Manufac- ture Number 4- Volts 5-Amps This tag can easily fall off. Without this tag, there are no other markings to identify this unit as a P/D type unit ver- sus the S/L terminal alternator. As soon as the tag is gone, you would normally pick this unit up and think to use the S/ L test lead to test the unit. I have developed a simple test to be used to identify and confirm a P/D alternator. The only tool you will need isa DVOM-digital volt ohmmeter. Set it on diode check. Attach the negative lead to the battery terminal of the al- ternator and attach the positive lead to the P terminal. There should be a read- ing of 0.9 to 1.1 volts. When the posi- tive lead is attached to the D terminal, the reading should be 0.5 to 0.7 volts. [have rechecked these figures on two P/D alternators. Ona S/L alternator the readings are higher. There is a special test lead needed to test this unit. The Northwest Regulator number is 889-PD. Page 1 of 2