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What can cause an ignition coil fuse to blow?

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June 28, 2019, 01:37 AM
thumperfbc
What can cause an ignition coil fuse to blow?
I was driving down the road in my 2002 F150 when it just died. No warning, just dead. It wouldn’t start. Strong cranking, no boom boom.

Had it towed home and started poking around. I watched a video on how to remove a coil (never done on this vehicle) and pulled in and checked for spark with a spare plug. No joy.

I thought the aftermarket alarm/starter might be malfunctioning and checked the fuses for it abd they were good.

On a whim I checked the fuse labeled ignition coils when I noticed it in the block. Blown. 30am fuse.

No spare so I stole the 30amp from the wiper curcuitbabd I was in business.

So the big question: what caused it to blow?
June 28, 2019, 02:41 AM
Jelly
Sometimes just age and duty cycles. Other times, a short in the circuit.
June 28, 2019, 03:13 AM
kkina
Bad ignition switch is most likely. Then check the rear O2 sensors (I think on the same fuse circuit), maybe a chafed wire is shorting out on the transmission.

Also do a quick check on the main engine ground strap. See if it's corroded or loose connection.



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