1997 Ford F150 Pick Up 5.0L engine with abnormal battery drain

Car wiring question


I noticed my engine is struggling when started during cold weather. Yesterday, I tried to measure to measure the battery drain as described in your test and I noticed it was close to 0.250 volt. This is strange because I just put a new battery in this truck 6 months ago. Do I have a problem here? I am just worried that this vehicle might leave me stranded but I don’t want to change any parts if I have too.

Vehicle wiring advice

For 1997 Ford models, a device called controls your battery GEM which stands for Generic Electronic Module. What it does is control all kinds of little gadgets in your vehicle (the ECM controls only the engine). One of them is called a battery saver relay. Here is how you can properly test your brain drain:

Hook up your digital voltmeter between the battery negative post and disconnected battery negative cable. If you get an extra higher voltage reading like 0.250 v, wait for about 1 hour and the GEM control will stop. When that happens, you should find the reading going to normal.

In case the battery readings remains high after the above test, try these:

Load test your battery strength level using a battery tester described in ats past newsletters. Put a battery charger on it for at least 2-3 hours. Measure the battery strength level again.

If the battery strength remains the same, you know for sure the battery is no good. Otherwise, there is a definite battery drain in your system.


What ever you do when working under the dash panel, do not touch the yellow-taped wiring harness to avoid accidental deployment of the air bag which will activate even with the battery disconnected. Remember: you do this service at your own risk.

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