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Hi all, I'm pretty sure I've got a short somewhere in the starter circuit.
Started with the starter not doing anything, even clicking. Ignition coil and ignition switch are fairly new.
Battery is good and have accessory power and lights.
So I replaced the starter. No change at all.
Checked the fuses. The 40 fuse for the starter was blown. While replacing it, it sparked a LOT and immediately blew.
Is that pretty much a short in the system and are there any tips for finding the sort other than going through the relevant wires until I see a crack in the insulation or exposed copper?
From: Jacksonville, FL (originally from Toronto Canada)
Originally Posted by coryforsenate
I'm not real good with strictly electrical issues but is the most likely culprit the ground wire that connects to the starter?
A "short" is a quick way of saying a "short to ground" which means that a power circuit is connecting to ground before the device it is supposed to power (it is reaching ground "short" of the load). Without that load, there is nothing to slow current flow so the current exceeds the capacity of the fuse and it blows. A ground wire already goes to ground (by definition) so it can't short to ground and can never be the cause of a fuse blowing.
I think MY_2K_Z may be on the right track for the source of your problem. Of course, I would have checked the fuse before replacing the starter.
I checked the heat shield and it's plenty out of the way of all the lugs on the starer.
Also undid the big wire from the frame mounting brackets that goes from the battery to the starter and did not see any cracks/damage to the insulation.
Is there another power wire to look for in the circuit? Only the large ignition A fuse is blowing, the large ignition B fuse is fine.
And I'm trying to look up to use my multimeter to test the fuse box itself before I try plugging in a fuse and potentially popping it and wasting $5. May I ask what setting to set my multimeter to to plug the leads into the holes where the fuse would go to test it? I keep googling and only finding instructions for how to test the fuse itself.
Here is the wiring diagram for my Chevy. I did not see any insulation cracks on the "red" wire that goes from the positive on the battery directly to the starter. Would the next likely culprit be the "red" wire that goes from the fuse to the relay switch?
From: Jacksonville, FL (originally from Toronto Canada)
What kind of vehicle is this? 98-02 F-bodies don't have a 40A "Ignition A" fuse, they power the starter relay through the 50A IGN fuse in junction block 2 under the hood... Junction block #2
It's a '96 C1500. I know this is more geared towards Chevy cars but I got into this forum when I rebuilt my 4l60E and I've found it much more helpful and active than other forums specifically for my vehicle.
Would a faulty ignition switch cause the ignition fuse to keep blowing even though the key isn't in? The ignition switch is fairly new and ACDelco OEM. I know they don't make parts like they used to but I'm hoping it didn't go out because that was a pain to replace when I did it.
I disconnected the ignition switch and then plugged everything else back in. Now the ignition fuse no longer pops.
I don't know if this means anything though but I'm trying to get as much information as possible to you guys to help me figure this out. I'm supposed to move to another city tomorrow and this is really bad timing to have a dead vehicle.
And here are the results. Everything has continuity except for an open loop when the key is in the off position. Would this explain why the ignition fuse keeps blowing and mean I have a bad ignition switch? ◢
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From: Jacksonville, FL (originally from Toronto Canada)
It is quite likely that the ignition switch is the source of your short since disconnecting it eliminates the fuse blowing. However, the open loop by itself would not be an indicator of a short. An open loop means that the two points you're testing don't connect to each other electrically (i.e. the circuit is "open"). That would normally mean that a wire is broken rather than shorted. But it is possible that the wire in question has broken and one of the broken ends is touching metal creating the short to ground. It's worth investigating. If your meter has a continuity setting, use it to test continuity between C1 and ground as well as between D5 and ground. If it doesn't have a continuity setting, you can do the same thing using the ohmmeter setting at its lowest range and looking for zero or near zero resistance between those pins and ground. If either of those pins shows continuity to ground then you've found your short.
It was the ignition switch. Replaced it and no more blown fuses and starter cranks no problem. Just in time because I moved several hours from College Station to Lubbock.
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Tips for finding a short in the starter circuit? 
