Auto Repair Q&A



Cooling System










Auto Repair Products

I have a 1995 Ford Thunderbird 4.6 V8. The battery keeps draining while the car is running. I have replaced the alternater and had both alternator and battery checked and they are good. The battery terminals are clean and secure. I can charge the battery

you have a short somewhere -

you have a short somewhere - disconnect neg cable - hook test lite between neg cable and engine bolt / ground - pull one fuse at a time - when the lite goes out thats your short

You are correct. I took the

You are correct. I took the ground wire off the battery and used a volt meter,I placed the ground wire on the neg terminal on the batt and placed the positive wire on a ground to the chassis and had a reading of 12.5 vdc. I pulled all fuses and relays in the car and under the hood with no change. Could the short be at the starter? Before doing this the car would not turn over but the batt was fully charged. The car acted like it had a low battery. Thanks in advance!!

take the starter off and have

take the starter off and have it bench tested

Am I right in undrstanding

Am I right in undrstanding that from time to time the engne will not spin over (even when the battery is fully charged)?

Is the starter solenoid clicking when you try to start the engine when you are having the "no-start" problem?

If starter checks out good, suspect the solenoid.

Sorry but your testing

Sorry but your testing procedure is wrong, and you will have to test again.


You use an (AMPMETER) and you are testing for (MILLIAMPS).

Copy and paste the link below into your address box then click on go.

Hook up an ammeter in series

Hook up an ammeter in series with either the (-) or the (+) terminal of the battery. There should be a reading if there is a drain. Isolate each accessary one at a time.When the reading is minimized you've found your culprit.You can also look for worn insulation on the wires,along the frame and anywhere wires contact metal.

The drain only occurs when

The drain only occurs when the the car is runnin? You're sayin there is no drain when the car is off? If that's the case then one or more diodes failed inside the alternator, and that in turn damaged the voltage regulator. Have the alternator professionally "Load Tested" just to be sure, but stand ready to replace it. If the battery is draning with the ignition off, the you have what is called a "Parasitic Battery Draw". You can "Google" the term to find out more information.

check alternator wires for

check alternator wires for damage or opens (something that might keep the charging voltage from reaching the battery).

Is this the first new alternator that you've put on the vehicle (sometimes even a new one is bad)?

Does the "BAT" light come on while you are driving the car?