Blowing 40 A starter fuses.

Blew one, last Spring, when I was feeling poorly, and relied on someone else to chase all the fuses. Result: AAA paid for a tow, and I paid the local Chevy emporium for a couple of hours of time, just to find the blown fuse. Fast forward to late Sept. and another blown fuse at startup, with a 15 second search under the hood disclosing the problem and we're on our way again, with misgivings. Since I had 190 K showing, I decides to rip out the starter and the alternator and have the local Mennonite handyman shop do their magic. Got two, basically brand new units back, the starter including new solenoid and drive. Two thousand miles later, here in sunny Port Charlotte FA, I came out of a Chinese restaurant and the dang fuse blew again after a couple of turns of the starter! Changed the fuse {a 50 A being the only one on hand} and it's going on it's marry way.

So, I thought I was on the right path, as the guys at Ferrels', back home thought that the old solenoid would quite possibly be the culprit, what with all the old-age and oxidation going on in there. What are some of your thoughts on the cause, and, or, cures of my problem. Don't know at this time if the 50 A fuse will hold indefinitely or not. Don't like the feeling of potential over-heating of wires. Though, I fail to see how dangerous two seconds of cranking could be. Your experience and advice will be greatly appreciated.

Thanks, DW

Well, since there are no responses, I'll just put the question to bed. Sort of.
I (may) have found the culprit, but only time will tell at this point.

Blown fuses continued, till early this week, when I blew two in succession. These last two wouldn't even make the solenoid click, before they were gone.

So, I swallowed my pride and took the Ford van over to the St. George garage and talked to the guys, there. Arranged to go back to the campground and cross up the starter posts and drive it back to have their guy look at it. Didn't happen that way! Had Jean watch the dash and turn the key to "run". The starter would turn the engine just fine, and the engine would fire just fine, but would shut off instantly, soon as I pulled my vise-grips away from the posts. Not a good feeling in my gut at that point. So, I got under the hood and into the UH power dist. box. I had blown a 50A fuse (ign A, always), so I had already tried jumping those two tabs with an alligator clip and smoked the tips of that, while Jean tried the starter. :o So, I turned the cover over, and, huh, here's a starter relay that I hadn't checked out. Duh! Pulled it, and it's neighbor (parking lights) and pushed it home. Stuck a 40A fuse in the ign A socket, reached in, across the wheel and hit the starter switch. VAROOM! Drove it back to St. George and talked it over with Kevin. Had Jean come and get me and left the Sierra with the garage for them to trace the circuit and make sure that there were no bare wires, or other evidence of shorts. Picked it up the next day with a brand-new relay in the starter socket and no shorts found. Thirty-five bucks, including the new relay, and all the discussion, plus the copy of the circuit that they had printed. About 150 miles on it, since, and many start-ups with no problems.

I'm impressed enough with these guys at St. George, that I'm going to put their info below for those who live near here, or might be in the area and need help. The cleanest garage I've ever seen. You could eat off the floor. I was referred by customers who have been pleased with their services, including my DIL's cousin who drives a pristine Corvette Indy. Pace Car, and is very particular. I'll be back there if the need arises.

St. George Automotive
7165 Gasparilla Road
Port Charlotte, FL 33981
Ph. (941) 698-9725

Thanks for providing a follow-up. Relays don't typically fail in ways that shorts a circuit. Normally, a relay fails due to burned contacts.
Jim

On re-read, I see that I mislabeled the fuse from the start. The blown fuse was ignition A - ignition B never did blow. So, on reflection, I'm still antsy about the relay being the final answer, remembering that the new 40 A fuse, last March, lasted all Summer, and the fault only returned in September. A study of the wiring diagram shows some interfacing of the ignition circuit(s) with the starter circuit, leaving me with some confusion and dread of a potential for the problem to return. With close to two weeks with no sign of a problem, I'm inclined to feel pretty good about it, but two years will confirm the solution.:D

Above my pay grade, but please keep us posted. My 2006 LBZ is getting close to 170K.