92 Ford Explorer will not start even when jumped

Alternator possibly.

Do you know where the starter relay is? If not do you know how to jump the starter

I would start with the battery first. If your battery lost 1 or 2 cells in it, jumping doesn't help. It's like try to jump a totally dead battery, you have to let it charge up some before it will crank over. Except with a dead cell, it never charges up.

Its a good possibility that the Anti-theft is interferring with the circuit. If you have an extra ignition key, use that in case the password chip in your regular FOB has detriorated.

There is a brake sensor which is on the upper brake pedal. It interlocks with the starter to prevent starting without having your foot on the brake pedal. Check your brake lights for operation. If the brake lights stay dark with your foot on the pedal, the switch is broke or knocked out of position. A common problem.

Next, there are small wires for the starter solenoid. You can use a test light on one removed wire and ground the test light to the vehicle, the other end in the small wire. Turn the keyswitch to start, with brake pedal pressed and see if it lights up. If it does light up, the starter solenoid may be bad.

Battery level. Ford Anti-theft and some say Battery-saver, can cause both starting and charging problems. A fully charged battery can be at 13.2V- 13.6V. When Ford systems detect low voltage it can activate the Anti-theft, battery-saver, and even disconnect the charging system to allow the battery to completely drain. In some cases the Anti-theft drops starter voltage to around 7V so the starter will not spin. Have the battery tested.

I know of 2004 trucks that were jump started and showed charging, then after 5-10 minutes they lost the charging system. Some people lost the charging system at 70MPH and drove until they stalled. All because of the automatic features built into the trucks. A new battery fixed the problem. Your problem could stem from this.

you have a bad battery or bad alternator, most parts stores can test both while in the vehicle.

first, if an auto trans, does it start in neutral? It could be a bad neutral - park safety switch.

The ignition siwtch could be bad too.

voltage regulator in alt gone bad..will strain battery

Normally a new battery would require at least 8 hours of continuous charging before it can take the full load of a vehicles lighting, starting motor etc...So please ensure that the new battery gets fully charged (ideally leave it charging for about 16 hours). I am not an expert on vehicles but I now this is how batteries (especially new batteries work). You would require a proper battery charge for this job because you cannot leave a another vehicle running with jump leads for this that long. Hope this helps.

Even though I bought the vehicle new, there was an aftermarket security system installed. The system had a bad diode, so i removed the system and reconnected the factory wires.

Return the battery and get another, sometimes because the battery set there too long and won’t work, I had twice when I had my Union 76 Station, after you try it, if you still can not start your son’s car. Let discuss more.