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ignition is off & 7.3 glo plug lead wire are 12v

2K views 3 replies 3 participants last post by  Steve83 
#1 ·
I've a 93 7.3 F350, non-turbo. I had my ignition turned off and did a gp check under the hood. I undid a gp wire lead at the gp top, attached the light probe to the positive battery post, touched the light probe to a gp post. Going through all eight, the probe light came on once (telling me that only one gp is good). When reattaching the gp wire leads to the gp tops, I accidentally grounded a couple of the wires, and they sparked sharply. I thought these wires wouldn't be "live", being that my ignition was turned off. Is that correct, shouldn't the gp wires be 0 volts? Can my ignition switch be bad? Thanks a lot.
 
#4 ·
Check the GP relay - it's just like this:



Unhook the small wire & listen for a CLICK. If it happens, the controller is holding the relay on. If not, remove the OUTput wire & test voltage from each big post to ground. If both are hot, the relay is welded together internally. If only the INput is hot, test from the output wire (the disconnected one) to ground. If it's hot, there's a short to power in the harness.
 
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