perplexing short?, ignition trouble |
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perplexing short?, ignition trouble |
Medtner3 |
May 29 2021, 10:07 PM
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#1
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Member Group: Members Posts: 180 Joined: 7-July 20 From: Cedar Park Member No.: 24,467 Region Association: None |
SOLVED: main ignition wire was shorted in the engine tunnel where repair work was done and mechanic (not me) cut the engine harness with a cutting tool and the shorted wire was grounded to the floor pan exposed where he cut a notch in the engine tunnel
I am starting a new thread on this issue: I can get my car to turn over if I jump the yellow wire under the passenger seat direct to the starter but when I run the yellow wire to the yellow and red wire that goes to the relay board it acts like a short and the wire heats up and won't crank. I suspected the relay board, so I took it off and turned upside down and checked continuity from the yellow wire where it enters the relay board and where it exits and there's continuity there and no apparent shorts I checked the exit yellow wire to the starter and has continuity, and likewise from the seatbelt interlock to the relay board and it also has continuity. What the heck? I seem to have perfect circuit here and no idea how it could be shorting I admit I am a dummy on electrical stuff so asking for help again |
ejm |
May 30 2021, 05:18 AM
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#2
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I can see the light at the end of the tunnel Group: Members Posts: 2,692 Joined: 3-February 03 From: Massachusetts Member No.: 224 Region Association: None |
Checking continuity will tell you if a wire has an open circuit but not if it is shorted to ground. With both ends of the wire disconnected check for continuity between the wire and ground to see if there is a short.
On the relay board there is a block of four connectors at the left rear corner. The two rear terminals are connected to the starter wire circuit and anything connected to those could also short the starter wire to ground. |
Medtner3 |
May 30 2021, 08:31 AM
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#3
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Member Group: Members Posts: 180 Joined: 7-July 20 From: Cedar Park Member No.: 24,467 Region Association: None |
Checking continuity will tell you if a wire has an open circuit but not if it is shorted to ground. With both ends of the wire disconnected check for continuity between the wire and ground to see if there is a short. On the relay board there is a block of four connectors at the left rear corner. The two rear terminals are connected to the starter wire circuit and anything connected to those could also short the starter wire to ground. I checked the first yellow / red to 14 pin connector. it is disconnected no short to ground when I connect the red lead to one end and the other to ground (shows OPEN LINE) no ohms. I checked the yellow wire from 12 pin connector to starter : same thing no short to ground: infinity ohms/OL. There is close to zero chance of a short from the 4 pin wire that goes to the ECU: it is new from Jeff Bowlsby although I examined it and it looks perfect. Possible relay board short?: How would I check the relay board? There is continuity between the 12 pin connector yellow wire (on pin 6) and the two lower prongs of the 4 pin, is there a way to check for short from the 4 pin connector in the relay board itself? My relay board looks like someone previously tampered with the connector that goes to the alternator no idea why. its's also very dirty and lots of corrosion in the heater fan so probably all the round plugs are corroded |
Medtner3 |
May 30 2021, 09:31 AM
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#4
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Member Group: Members Posts: 180 Joined: 7-July 20 From: Cedar Park Member No.: 24,467 Region Association: None |
Checking continuity will tell you if a wire has an open circuit but not if it is shorted to ground. With both ends of the wire disconnected check for continuity between the wire and ground to see if there is a short. On the relay board there is a block of four connectors at the left rear corner. The two rear terminals are connected to the starter wire circuit and anything connected to those could also short the starter wire to ground. I checked the first yellow / red to 14 pin connector. it is disconnected no short to ground when I connect the red lead to one end and the other to ground (shows OPEN LINE) no ohms. I checked the yellow wire from 12 pin connector to starter : same thing no short to ground: infinity ohms/OL. There is close to zero chance of a short from the 4 pin wire that goes to the ECU: it is new from Jeff Bowlsby although I examined it and it looks perfect. Possible relay board short?: How would I check the relay board? There is continuity between the 12 pin connector yellow wire (on pin 6) and the two lower prongs of the 4 pin, is there a way to check for short from the 4 pin connector in the relay board itself? My relay board looks like someone previously tampered with the connector that goes to the alternator no idea why. its's also very dirty and lots of corrosion in the heater fan so probably all the round plugs are corroded Attached thumbnail(s) |
Medtner3 |
May 30 2021, 11:44 AM
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#5
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Member Group: Members Posts: 180 Joined: 7-July 20 From: Cedar Park Member No.: 24,467 Region Association: None |
Checking continuity will tell you if a wire has an open circuit but not if it is shorted to ground. With both ends of the wire disconnected check for continuity between the wire and ground to see if there is a short. On the relay board there is a block of four connectors at the left rear corner. The two rear terminals are connected to the starter wire circuit and anything connected to those could also short the starter wire to ground. I read somewhere that someone else had the problem of continuity between the 14 pin connector and 12 pin connector even though it showed open it hadvery inconsistent through the whole copper tracing |
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