I have a 1995 4.0 Aerostar. What started the problem was both low beam elements blew out at the same time. After replacing both bulbs, I now have the following problem. When using high drain items such as headlights, heater blowers (front or back, or both, it makes no differance), electric windows, the battery gage drains. It doesn't matter if at idle or under regular driving conditions. If I turn off all said items, the problem stops. I have had the alternator and regulator checked and both are fine. All fuses and fuseable links are also in good condition. Battery is fully charged. Wires and terminals are clean. While I can drive fine on sunny and warm days, I live in Washington State. So, I need as much help as possible. I am wondering if it may be the relay next to the battery.

Thanks!
Aeaton9021

 

So the battery is retaining its charge? Have you taken the vehicle out for a long drive using the functions that draw the gauge down? Try it and see if the battery goes dead. If the battery remains charged, then you could have a problem in the amp gauge circuit (gauge or wiring).

 

I have taken it on drives of varing lenghts, from 20 miles to 2 blocks. The problem does not change, the battery charge stays the same. All wires appear normal. No fraying, not brittle, not melted, no shrinking or thickening. None appear burnt. Same thing with fuses and fusable links. I am leaning towards the starter relay or else a switch that is not working and allowing a circuit to close.

Thanks!
Aeaton9021

 

Sounds like a gauge problem. I wouldn't suspect the starter relay if the starter isn't engaging. When the engine is at idle, and you turn accessories on, does the headlights dim as the amp gauge drops? If not, the alternator is charging the electrical system and the gauge circuit should be looked at.

I have the book in front of me. If you could try it out and let me know real quick, I'll provide you with more advice (it's 11:05 here in the Azores).

 

At idle gage drops, no dimming of lights. Gage only does this when high drain items are in use.

 

What does the gauge say? Measure the volts at the battery with the engine running. If it is different than the volts on the gauge, check the gauge. Pull the gauge and substitute a voltmeter and measure. This will verify the condition of the gauge for you.

 

Here is a reprint of my own experience with the mysterious loss of power. It took almost 7 months to find the problem and has not reoccured since. Also, the power readings are much higher now than they have ever been. Been close to 1 year and no problems at all.

Hope this helps!!

John


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At Wit's End Electrical
I think I have found the problem to the weird occasional power problem and a previous problem that re-occured where all power in the car would go away and suddenly come back when you closed the hood or shook the wires.

The problem re-occured a few nights ago. After going for several days without major problems, my wife drove home from work and when she turned off the engine, once again all power was gone in the car. I came out and shook everything carefully and finally found the wire that was causing the problem.

There is a red wire between the starter solenoid on the starter and the starter relay on the top driver side of the engine fender wall. It is a 10 guage wire and gets bolted on by itself on one of the terminals on the relay. When I carefully would shake this, it would cause all power to go out and then all power to go back on. What did not make since was, when I took the wire off completely, the power would be on, but of course the starter would not start.

I determined the top 8 to 10 inches held the problem, so I cut off that portion, including the terminal crimp, and then stripped all the insulation off to see what the wire looked like. The top 6 inches were very black, as if it was arcing, but the wire was not broken in any way.

I crimped a new piece of wire and new terminal eye onto the existing wire and reconnected it and the power seems very stable now with no strange symptoms.

I can only guess that somehow moisture got into the wire and slowly caused it to deteriorate. Under certain conditions the wire would arc inside and trip some kind of circuit breaker in the electrical circuit. I really have no idea why this wire that was not shorting out against anything elese could cause all power in the car to stop, but hopefully, it's repair has caused the problem to go away. I will totally replace the wire soon.

Sorry for the long message but this has gone on so long I felt a full explanation was warrented.

John