RustyPile
Left on own accord
- Joined
- Oct 7, 2017
- Posts
- 901
- Reaction score
- 1,124
- Location
- Elkhart, TX
- First Name
- Nick
- Truck Year
- 1983 GMC
- Truck Model
- 1500
- Engine Size
- 350 SBC
[EDIT --- Yes Rick, I know for a fact the "sender" as you call it is a circuit breaker and not a flasher relay. I've had mine apart. I've also made two or three of them using a variety of breaker values. Take yours apart and see for yourself.. On a lesser note... I assume responsibility for you finding the lost MVI, but not your loosing it (;-)]
Come on Rick.. You don't have a reputation of not thoroughly reading these posts. (I' can't find the smiley face) I stated my ownership and use of tool in my post that you quoted.. I've even made mention of the fact over the years I've been here. Suggested others use it also and posted the link numerous times.
I'm not exaggerating the simplicity of its use.. The "secret", if there is one, is how the ammeter works.. It's a zero center meter.. It know which direction the current is flowing. It always points in the direction of the short along the harness.. If, in the process of following the harness and the harness "Ts" off and you continue straight, the needle points the other way, back in the direction of the "T". If WILL NOT lead you down a rabbit hole..
It proved it's worth to me a long time ago when I was still employed.. A friend of mine brought his wife's (cough, cough) Ford Taurus to me.. He had a couple problems he wanted me to look at.. Occasionally, the CHECK ENGINE light would come on briefly and go out.. As you know in those early days of engine management computers, Ford required a breakout box in order to monitor the data stream. There was no ALDL plug and diagnostics were expensive when the breakout box was required. He'd taken to car to a dealership a few times and they couldn't find the cause of the problem.. The second problem was the tail light fuse would blow on occasion.. Again, the dealership couldn't find the problem, and now the fuse would blow as soon as the lights were turned on..
I hooked up my short finder and went to work.. Expecting it to guide me toward the rear of the car, I was surprised when it "led" me through the firewall and forward along the harness branch on the engine cradle going forward toward the radiator. It puzzled me why the taillight harness would take that route but I trusted the tool and continued on..
When I reached one of the engine mounts, I found the harness was tucked up tight against it. The needle stopped right there, indicating the location of the short.. I gave the harness a tug and discovered a small bit of it was pinched between the frame and engine mount.. I unbolted the mount and freed the harness.. Low and behold a wire color coded for tail lights was pinched and shorting to the frame.. I repaired the wire and began to investigate why the CHECK ENGINE light was coming on.. It turned out the computer, for some reason known only to FMC, needs to know when the tail lights are on.. This shorted wire is the wire carrying that signal, and with the wire shorted to ground, the computer never, ever received that signal and I suppose "curiosity" made it set the CHECK ENGINE light..
It took me longer to type this three paragraph narrative than it took to actually locate that short.
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